Bu,«»N..M ^ESS&KSP'* 

DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

CHARLES D. WALCOTT, DIRECTOR

CONTRIBUTIONS TO MINERALOGY

FROM THE

UNITED STATES GEOLOGICAL SURVEY

BY

F. W. CLARKE, W. F. HILLEBRAND, F. L. RANSOME, S. L. PENFIELD, WALDEMAR LIND6REN, 

GEORGE STEIGER, AND W. T. SCHALLER

WASHINGTON

GOVERNMENT PRINTING OFFICE

1905 '

CONTENTS.

Tago. 

Letter of transmittal, by G. F. Becker ..................................... ' 5

Prefatory note, by F. W. Clarke........................................... 7

On carnotite and associated vanadiferous minerals in western Colorado, by

W. F. Hillebrand and F. Leslie Bansome ................................ 9

Some additions to the alunite-jarosite group of minerals, by W. F. Hillebrand

and S. L. Penfield.................................................L.... 32

Minerals from the Clifton-Morenci district, Arizona, by Waldemar Lindgren

and W. F. Hillebrand.................................................. 42

Two tellurium minerals from Colorado, by W. F. Hillebrand.....i.......... 55

Notes on lawsonite, by W. T. Schaller and W. F. Hillebrand................ 58

The composition of yttrialite, with a criticism of the formula assigned to

thal&iite, by W. F. Hillebrand.......................................... 61

A pseudo-serpentine from Stevens County, Wash., by F. W. Clarke.......... 69

On " californite," by F. W. Clarke and George Steiger...................... 72

The action of silver nitrate and thallona nitrate upon certain natural silicates,

by George Steiger ........................................................ 75

Dumortierite, by W. T. Schaller........................................... 91

Mineralogical notes, by W. T. Schaller..................................... 121

Index .........-...--.._-.-..-...---- --...---.---..-----------.--..---. 145

3
ILLUSTRATIONS.

FIG. 1. Natrojarosite .................^...i...........................j... 32

2. Plumbojarosite ................................................... 35

3. Dioptase ..............!:.......................................:. 46

4. Libethenite.......................'................................ 51

5. Lawsonite........................................................ 59

6. Dumortierite altering to muscovite ................................. 101

7. Forms of dumortierite............................................. 104

8. Dumortierite ...................................................... Ill

9. Tellurite ......................................................... 127

10. Anhydrite. ......................................................... 132

11. Glaucodot............................-.-.---.-......---.-..-.---. 133

12. Libethenite-......-...-.---......--.-.-...-..-....----..---.--..-- 141
LETTER OF TBANSMITTAL.

DEPARTMENT OP THE INTERIOR,

UNITED STATES GEOLOGICAL SURVEY, 

' Washington,]). C., January 31, 1905.

SIR: I have the honor to transmit herewith a series of papers by 

various hands for publication as a bulletin. They represent mineralogical investigations incidental to geological researches arid important 

to the progress of geology, and are here brought together for convenience of reference.

Very respectfully, G. F. BECKER,

Geologist in Charge Division of

Chemical and Physical Research.

Hon. CHARLES D. WALCOTT, 

Director United States Geological Survey.

CONTRIBUTIONS TO MINERALOGY FROM THE UNITED 

STATES GEOLOGICAL SURVEY.

PREFATORY NOTE.

By F. W. CLAKKE.

Although mineralogical research occupies a relatively small place 

among the many varied activities of the United States Geological 

Survey, it is by no means neglected. From time to time interesting 

material is collected by the field parties of the organization, and specimens deserving study are received from other sources. These are 

worked up, as opportunity offers, in the chemical laboratory of the 

Survey, sometimes independently and sometimes, as in the work 

reported in two of the memoirs here presented, in cooperation with 

the geologists by whom they were brought in. Occasionally assistance 

is received from investigators not connected with the Survey, and one 

such case is now represented by the joint paper of Doctor Hillebrand 

and Professor Penfield. of Yale University. In that instance the 

chemical work was done in Washington and the cry stall ographic 

measurements were made at New Haven.

Most of the papers contained in this bulletin represent investigations 

which are complete within themselves. The work done by Mr. 

Steiger upon the silver and thallium derivatives of the zeolites, however, is to be regarded as one part of a series of researches upon the 

constitution of the silicates. Some parts of this series have been 

already published, and it is hoped that this work may be continued in 

the future. The field to be covered is enormous and progress within 

it is necessarily slow. Still, the results obtained so far are definite and 

significant, especially as they show a chemical plasticity among the 

silicates which was formerly unsuspected.

Some of the items of more than ordinary interest to be found 

within these pages are as follows: Three new mineral species morencite, coronadite, and plumbojarosite are described. Natrojarosite,
8 CONTRIBUTIONS TO MINERALOGY. [BULL.202.

although, not* absolutely new, is now thoroughly established as a 

definite mineral. The true character of carnotite is shown in Doctor 

Hillebrand's research, and the same chemist has worked out more 

fully than his predecessors the composition of yttrialite and its relations to other species. Mr. Schaller's very complete study of 

dumortierite is also worthy of especial mention, and his notes upon 

other minerals from California are but the first fruits of .a much 

larger research which is already well under way.
ON CARNOTITE AND ASSOCIATED VANADIFEROUS MINERALS 

IN WESTERN COLORADO.

By W. F. HILLEBRAND and F. L. RAN SOME.

INTRODUCTION.

By W. F. HlLLEBRAND.

The rather widespread occurrence in western Colorado of considerable quantities of a canary-yellow ore of uranium has been known for 

a few years past. It has been marketed to the extent of a few tons, 

but its mineralogical nature was unknown or incorrectly surmised 

until 1899.

In the spring of that year a specimen of this ore first reached my 

hands through Dr. George P. Merrill, of the United States National 

Museum, and v.as soon found to contain a mineral or minerals new to 

science. Within a week appeared the announcement by MM. C. Friedel 

and E. Cumenge" of a new mineral, carnotite, a hydrous vanadate of 

uranium and potassium, obtained through Mr. Poulot of Denver, from 

Roc Creek, Montrose County, Colo. Mr. Poulot had already identified vanadium in it. It was at once seen, despite certain differences 

in composition, that the two were identical.

According to the French authors the mineral is of simple composition, as above expressed, with only a little iron and mere traces of 

Al, Ba, Cu, Pb, and also, according to M. and Mme. Curie, of the 

radio-active substances radium and polonium. The empirical formula 

2UaO3 , V2Or> , K2O, 3Hj,O, was^ssigned to it, some doubt attaching to 

the Avater.

- Since then I have been able to examine carnotite from several localities in western Colorado, finjding in each case the same lack of agreement with the analyses of Friedel and Cumenge.

While I was engaged in this work my attention was called to certain 

more or less greenish sandstones from the vicinity of Placerville on 

the San Miguel River, San Miguel County, Colo., which were said to 

be highly vanadiferous and of considerable extent, and in which a zone

(iBull. Soc. Chim. de Paris (3), xxi, 328,1899; Bull. Soc. Franc. Min., xxii, 26,1899; Comptes Rendus, 

cxxviii, 632,1899; Chemical News, Ixxx, 1C, 1899. The papers as published in French differ slightly.
10 CONTRIBUTIONS TO MINEKALOGY. [BULL. 202!

a few inches thick was rather strongly impregnated with a yellow 

mineral resembling and probably identical with carnotite. This mineral appeared also scattered through the sandstone at other points in 

sporadic small patches, sometimes visible only by aid of a lens.

This occurrence led to the thought that the carnotite bodies farther 

west might also be associated with existing or dependent on preexistent vanadif erous sandstones. For the carnotite of Montrose and Mesa 

counties, as is stated by the French authors, occurs mixed in all proportions with quartz-sand grains, the remnants, beyond doubt, of 

former sandstone bodies, and it was soon recognized that in the carnotite bodies the vanadium existed in two conditions, the larger part 

b}r far as pentavalent vanadium in the easily soluble carnotite, and a 

smaller and sometimes hardly distinguishable portion as trivalent vanadium in a much less soluble silicate which was free from uranium.

It was hoped that, by a field reconnaissance, observations bearing 

on these points would be obtained and material assembled which would 

on analysis help to determine the nature and explain the association of 

these two entirely different classes of mineral substances.

The field and microscopical observations of Messrs. Ransome and 

Spencer are embodied in the pages immediately following these introductoiy remarks. Unfortunately their collections, except those from 

Placerville, came to hand so late that the chemical work on the more 

western occurrences has been confined to the carnotite bodies alone, 

specimens of which were already in my hands. Greenish sandstones 

have been observed by Messrs. Ransome and Spencer in those regions, 

but whether any of them are highly Vanadif erous, or what their connection with the carnotite may be, remains yet unknown. The only 

two examined did not owe .their color to vanadium. Meanwhile the 

chemical results thus far obtained will be found in the.concluding section of this paper.

In this place it is my pleasure to record my appreciation of the 

readiness with which the following gentlemen have supplied me with 

material for study: Messrs. Poulot and Voilleque of Denver, Mr. A. 

B. Frenzel of Placerville, and Mr. J. R. Duling of Paradox. These 

gentlemen have also not hesitated to give me all information at their 

disposal as to occurrence and field relations of these interesting ore 

bodies.

OCCURRENCE OF THE URANIUM AND VANADIUM ORES.

By F. L. RANSOME. 

GENERAL STATEMENT.

In the autumn of 1899, accompanied by Dr. A. C. Spencer, whose 

knowledge of the stratigraphy of the region was of great assistance, 

I made a hasty reconnaissance trip into the western portions of 

San Miguel, Montrose, and Mesa counties, near the Utah-Colorado
KANSOME.] CARNOTITE AND ASSOCIATED MINERALS. 11

line. The primary object of the expedition, in accordance with a 

suggestion from Mr. S. F. Emmons, was to investigate the copper 

deposits of La Sal Creek, Paradox and Sinbad valleys, and the vicinity, 

which had been the occasion of some mining excitement a few months 

before. A memorandum from Dr. W. F. Hillebrand, received just 

before starting, indicated that it would be well also to examine certain 

prospects on which some preliminary work had been done, looking 

toward the extraction of ores of uranium and vanadium. It is to these 

ores that the present notes are confined.

The most convenient way of reaching Paradox -Valley was found to 

be the stage road, which, starting from Placer ville, a settlement and 

station on the Rio Grande Southern Railroad, runs by way of Norwood, Shenandoah, and Naturita to Paradox, a distance of 60 or 70 

miles. The region can also be reached from the west by way of

Moab, in Utah,

The topography of the region west of Placer ville is that characteristic of the "mesa country" of western Colorado and southeastern 

Utah. Broad stretches of plateau are intersected by steep-walled 

canyons and cliff-encircled valleys. The underlying rocks comprise the 

"Red Beds" of the Dolores formation a (Triassic), the La Plata formation (Jurassic), the McElmo formation (Jurassic), the Dakota sandstone (Cretaceous), and the Mahcos shales (Cretaceous). Carboniferous rocks occur in Sinbad Valley, and a series of gypsum-bearing 

shales of unknown age is found in the bottoms of Sinbad and Paradox 

valleys, but as the ore deposits to be described all occur in the beds of 

the La Plata and McElmo formations, these older rocks need not again 

be referred to. The sediments making up these various formations 

lie usually nearly horizontal, but they are sometimes flexed and frequently faulted.

In all of the prospects examined the ore of uranium occurs in the 

form of the recently described bright-yellow carnotite. In one case 

this is intimately associated with a dull olive-green mineral which, 

according to Doctor Hillebrand, is either identical with, or very closely 

allied to, the vanadium-mica roscoelite. Deposits of one or both of 

these minerals occur widely scattered over San Miguel and Montrose 

counties, Colo., and in the Blue Mountain (Sierra Abajo) district of 

southeastern Utah; but only a few of the known deposits were personally examined.

PLACERVILLE DEPOSITS.

These are essentially vanadium deposits, and occur 4,500 feet nearlynortheast of the railway station near Placerville, and about 1,000 feet 

above the San Miguel River. The lower 900 feet of the San Miguel

"The formation names used in these notes are those adopted by Mr. Whitman Cross in the text of 

the Telluride folio (folio 57), of the U. S. Geological Survey. The reader is referred to this folio for 

fuller descriptions.
12 CONTRIBUTIONS TO MINERALOGY. [BUM..202.

canyon is cut in the characteristic '' Red Beds " of the Dolores formation. 

Above the Dolores comes the La Plata sandstone in typical development, as described in the Telluride folio, viz, two heavy beds of lightcolored sandstone, separated by a much thinner bed of dark limestone. 

The roscoelite occurs as an impregnation in the lower bed of the La 

Plata sandstone, about 100 feet above the base, and just beneath the 

bed of dark limestone. All the beds at this point are practically horizontal. The dark green vanadiferous sandstone occurs in a nearly 

continuous band, approximately parallel to the bedding planes, and 

varying in thickness from a few inches up to 5 or 6 feet. This band 

extends along the sandstone cliffs for an estimated distance of about 

2,000 feet. The roscoelite more or less thoroughly impregnates portions of the fine-grained sandstone which constitutes the mass of the 

bed. It sometimes makes up more than 20 per cent of the vanadif-- 

erous facies. Normally the sandstone of this lower bed of the La 

Plata is light buff in color, with patches, mottlings, and stripes of pale 

pink, the latter color being apparently due to small amounts of ferric 

oxide. But when richly impregnated with roscoelite this light-colored 

sandstone becomes dark olive-green, the contrast being most marked 

when the cliffs are wet. Although fairly continuous for the distance 

stated,.this zone of vanadiferous sandstone is by no means regular. 

It varies much in thickness, and in one place splits into two or more 

branches. At some points two or more distinct streaks of roscoelitebearing sand were found at different horizons in the main sandstone 

bed. The carnotite is not nearly so abundant as the roscoelite at this 

locality. It occurs as minute yellow specks in the sandstone, and particularly as thin horizontal seams or streaks near the bottom of the 

vanadiferous zone. 

The work thus far done on the several claims which have been

located along these deposits is of the most superficial character. On 

the Canary claim Mr. A. B. Frenzel has run a tunnel, about IS feet 

long, which exposes a typical section of the impregnated zone. The 

roof of the tunnel is formed by the under side of the bed of dark limestone previously referred to. This limestone is underlain by a few 

inches of sandy limestone which passes into the light-buff La Plata 

sandstone without break. The latter contains abundant calcite as a 

cement or matrix for the sand grains. At a distance of a foot below 

the limestone, the sandstone shows, on close inspection, numerous 

specks of carnotite and gives a qualitative reaction for vanadium 

(Hillebrand). Examined in thin section under the microscope, this 

portion of the bed shows a fine-grained homogeneous sandstone, in 

which well-rounded grains of quartz are held together by a rather 

abundant matrix of calcite. The calcite is crystallized as a fine granular aggregate and includes small indeterminable particles of various 

kinds. Many of the quartz grains, as seen in section, are entirely 

surrounded by calcite, and so isolated from adjacent grains. A pale
BANSOME.J CAKNOTITE AND ASSOCIATED MINERALS. 13

i

lemon-yelloAV substance occurs sporadically in the section as an interstitial material between the quartz grains. This is probably the carnotite, which was seen as small, yellow specks in the hand specimen. 

It is very minutely crystalline, recalling the habit of some obscure 

chloritic aggregates in decomposed igneous rocks, and is too indistinct 

for successful optical study. Small crystal grains of zircon are scattered through the sandstone, and are readily concentrated in the residue after treating with hydrofluoric acid.

Within the next 2 feet below the zone where it exhibits the foregoing facies, the sandstone becomes pinkish in consequence of the 

presence of ferric oxide, and in this pinkish rock the lens fails to 

reveal any roscoelite or carnotite. But just below the pink zone the 

sandstone begins to show yellow and green specks. The latter especially become more numerous and larger, until at from 3 to 4 feet 

below the limestone the sandstone has a decided green tint. Farther 

downward this deepens, until near the floor of the tunnel the sandstone 

is a uniform deep olive-green. This green rock is rich in roscoelite 

(over 20 per cent) and shows many small yellow specks of carnotite. 

This is regarded as the first-class ore, and the chief value of the deposit 

is supposed to be in its vanadium, the uraniunl being very subordinate. 

In this respect the Placerville deposit differs from those on La Sal and 

lioc creeks, presently to be described, where the mineral sought for 

and occurring most abundantly is carnotite.

Thin sections of the green-spotted sandstone, when examined microscopically, resemble those of the light-buff sandstone just above it, as 

far as character of quartz grains and relative abundance of matrix are 

concerned. . But the character of the matrix or cement is different. 

Calcite is much less abundant and its place is largely taken by roscoelite. This is grass-green in thin section, and might readily be mistaken for indistinct wisps and areas of chlorite. It sometimes forms 

a distinct envelope around the quartz grains, showing an indistinct 

foliated or fibrous structure, with the fibers normal to the surface of 

the grains.

The uniformly dark-green sandstone, richest in roscoelite, does not 

effervesce with acids and shows no calcite cement in thin section. 

The usual quartz grains are held together by roscoelite. This is crystalline, but the highest available powers show only an indistinct and 

minute foliation, such as may be observed in some very finely crystallized chlorites.

Close to the floor of the tunnel is a fairly regular, nearly horizontal 

streak of carnotite, varying in width, but usually less than an inch 

wide, and showing noticeable diminution in thickness in the face of 

the tunnel. This small seam is not solid carnotite, but is merely a 

zone in the sandstone impregnated with the bright-yellow uranium 

mineral. It is not nearly so continuous as the main vanadiferous belt, 

and was seen only at three or four places along the outcrop of the
14 CONTRIBUTIONS TO MINERALOGY. [BULL.262.

belt, which extends for a distance of about 2,000 feet. When this 

seam is closely examined it is seen that narrow bands rich in carnotite 

alternate with, green bands carrying mostly roscoelite. There is also 

usually present a seam of almost pure quartz, generally about an 

eighth of an inch in thickness, though often thicker. The microscope 

shows it to be a true quartzite, in which the original rounded detrital 

grains of quartz have been cemented by fresh quartz in optical continuity with the older granules. A similar quartzite occurs in the 

green vanadiferous sandstone above the carnotite, where it forms concretionary knots and nodules. It was not noted in the buff sandstone, 

however, where the cementing material is calcite.

Immediately below the carnotite seam there is a parting or "floor" 

in the sandstone, probably originally a very thin layer of shale, which 

forms the working floor of the tunnel. The sandstone below this 

floor is plainly impregnated lor a short distance with roscoelite, but 

the thin shale seam is regarded as the practical bottom of the deposit.

The questions of the origin and actual extent of this deposit are 

closely related and are of much interest. Their discussion will be 

deferred until the other deposits visited have been described.

Some distance below the Placerville vanadium deposit a zone of 

green sandstone, presumably belonging to the Dolores formation, was 

observed. This color is a somewhat brighter green than that of the 

vanadiferous sandstone higher up the slope. As there are some copper prospects near by, from which ore has been taken, this was supposed to be a copper stain. Qualitative tests by Doctor Hillebrand 

show, however, that.the color is due to a compound of chromium.

Similar green sandstones occur on the western side of Sinbad Valley 

in what is apparently the La Plata formation, and were originally 

supposed to be impregnated'with roscoelite. Doctor Hillebrand's 

investigations, however, show that they too owe their color to some 

chromium mineral. These occurrences are interesting as showing 

that a green color in sandstones may result from various causes, and 

that even a bright green tint can not be taken as an infallible indication of copper.

LA SAL CREEK DEPOSITS.

These occur in the extreme western portion of Montrose County, 

southwest of Paradox, and about 6 miles up La Sal Creek from Cashin. 

They are reached by trails from Paradox Valley and from Cashin. 

The deposits are on the south side of La Sal Creek and about 700 feet 

above the stream. They occur for a distance estimated at more than 

a quarter of a mile, along the sandstone cliffs which descend from the 

mesa into the canj^on of La Sal Creek, and only a few feet below the 

level of .the mesa surface.

In the absence of continuous stratigraphic work, it is impossible 

to correlate certainly and finally the rocks on La Sal Creek with the 

divisions established by Cross and Spencer in the Telluride quadrangle,
RANSOME.] CARNOTITE AND ASSOCIATED MINERALS. 15

which lies just east of this area. It seems probable, however, that the 

La Plata sandstone attains a much greater thickness in this portion of 

western Colorado than it does between Telluride andPlacerville. The 

limestone bed, so characteristic a feature of the formation near Placerville and farther east, is not .uniformly present in this western region, 

and the La Plata sandstone (Variegated beds, in part, of the Hayden 

survey) is not always readily differentiated from the underlying 

Dolores formation (Red Beds). For a vertical distance of about 400 

feet above the bed of La Sal Creek the rock is a heavy-bedded, rather 

fine-grained, light-colored sandstone, which is considered by Doctor 

Spencer to be the La Plata. Above this come thinner-bedded sandstones, with some conglomerates and shales, which are included in the 

McElmo formation. It is in this upper series that the uraniferous 

deposits occur. All the beds are here approximately horizontal.

As revealed by numerous small openings near the crest of the bluff,

the carnotite, which is the material here sought, is found chiefly in a 

massive bed of nearly white sandstone. Some of the ore, however, 

lies between the sandstone and a lower bed of light-gray shale. 

Although the prospecting openings all lie at about the same level 

along the cliffs, the deposit is not nearly so regular as the vanadif erous 

band near Placerville.

The carnotite of La Sal Creek occurs as irregular, bunchy "pockets" 

in the sandstone, or along the contact of the sandstone with the underlying shale. These have all the appearance of being impregnation 

deposits, the solutions carrying the uranium compounds having deposited the. ore wherever they found ready passage through the rock usually along bedding planes. No roscoelite was seen with the carnotite.

The most remarkable and interesting fact in regard to the La Sal 

Creek deposits is their very superficial character.8 The ore bodies are 

usually flat-lying streaks, a few inches thick, which grade above and 

below into the common light-buff sandstone, and which die out and 

disappear when followed into the hillside. In tunnels that run but a 

few feet underground the yellow impregnation of carnotite can be seen 

gradually to die out and to be succeeded by light-colored sandstone, 

showing no trace of the mineral. It is doubtful whether any appreciable quantity of carnotite occurs as much as 20 feet from the surface, 

on any of the locations, although this distance is given from memory 

and not from measurements on the ground. As before stated, the 

impregnation has usually taken place along bedding planes; it has also 

proceeded along surfaces of minor and superficial movement in the 

rocks. In one case it was observed that a portion of the overlying 

sandstone had moved upon the underhdng shales, the disturbance being 

apparently a superficial one, of a kind commonly enough observed 

where massive beds rest on yielding shales on a steep hillside. In 

other words, the movement appeared to be directly related to the 

present topography, 7,'he carnotite was here deposited subsequent to
16 CONTEIBUTIONS TO MINEKALOGY. [uui,L.262.

the movement and had filled the small openings and dislocations in the 

shale caused by this very recent disturbance. It was reported that 

some of the best nests of ore had been found in "slide rock," i. e., 

rock which had slipped to some extent down the slope; but I was 

unable to verify this statement further than is indicated in the preceding description. There can be little doubt that the deposits of carnotite on La Sal Creek are not only very superficial in character but 

very recent in age.

ROC CREEK DEPOSIT.

The principal claim is the Copper Prince, owned by J. R. Duling, 

on the north side of Roc Creek, 3 or 4 miles above its mouth, and near 

the foot of the Miller trail to Paradox. It is reached by this trail from 

Paradox Valley, or by trail from Hydraulic on the Dolores River. 

This deposit is in the La Plata sandstone, according to Doctor Spencer's observations, and has been more extensively exploited than any 

other seen. The sandstone, which at this point is nearly horizontal, 

is cut by an east-west fault, the fault plane dipping north at about 70°. 

The amount and character of the throw could not be determined. It 

is probably less than 50 feet. The carnotite occurs in the hanging wall 

of the fissure as small irregular branches in a loose mass of crushed 

sandstone and also as an impregnation of some of the firmer portions 

of the bed. No roscoelite was seen. Several small tunnels have been 

run in on the hanging wall side of the fissure (which itself carries no 

vein or ore-body), but they had been securely closed by planking, and 

no examination of their inner ends could be made. I am thus unable 

to tell what changes the deposit would show if it could be followed 

inward from the surface. A few hundred pounds of picked carnotite 

ore has been shipped from this claim and is reported to have sold for 

$1.25 a pound in Denver. This deposit is similar in character to others

examined, except that in this case a well-defined fault has provided a 

zone of crushed and porous rock in the hanging wall, along which 

impregnation could take place. A few hundred feet farther west the 

crushed sandstone adjoining the fault has been impregnated with 

cupriferous solutions and is spotted with stains of the blue and green 

carbonates of copper.

OTHER DEPOSITS.

It is known that several carnotite claims have been located in 

Gypsum Valley in what is known as the Disappointment district. 

The impregnated sandstone is said to cap a hill and to constitute an 

extensive deposit, but it was not visited. Carnotite is also reported 

from the Blue Mountain district, but I have no personal knowledge of 

these occurrences. It seems highly probable that the material will 

be found widely distributed in the Mesozoic sandstones of western 

Colorado and eastern Utah, although perhaps nowhere, in very extensive bodies.
KANSOME.] CAKNOTITE AND ASSOCIATED MINERALS. 17

ORIGIN OF THE DEPOSITS.

That the bodies of carnotite and roscoelite were formed subsequently 

to the deposition of the sandstones is evident from the facts presented 

in the preceding pages. It is equally plain that the minerals could not 

have resulted from the alteration, in place, of other compounds of 

vanadium and uranium originally contained in the sands. The shape 

and position of the deposits indicate clearly that the ores have been 

brought to their present position by transportation. Moreover, the 

recency of the deposits and the fact that they are sometimes directly 

connected with faults and dislocations in the sandstones show that the 

vanadium and uranium compounds could not have been the original 

cementing material of the quartz grains, but in all probability they 

'have locally replaced the calcite that acts as matrix to the ordinary 

light-colored sandstone in which the ore bodies occur. The deposits 

of roscoelite appear to be comparable to impregnations formed in 

sandstones by cupriferous solutions such impregnations as ma}r be 

seen at many places in this region, particularly on La Sal Creek near 

Cashin and in Sinbad Valley whereby the sandstone becomes colored 

bright green with carbonate of copper. In these places, however, the 

copper appears to have been previously deposited in part as chalcocite. 

An analogy might also be drawn with the green chromiferous sandstone near Placerville, already referred to. In all these cases the 

actual sources of the materials which have been deposited by solutions in their present position are not known. Doctor Hillebrand 

has shown,a however, that vanadium in small amounts is widely distributed in sandstones, limestones, and igneous rocks. It is perhaps 

present in very small amounts throughout the sandstone, and the 

deposits described may simply represent a concentration of this material under certain favorable conditions of solution and redeposition.

In the absence of exploitation it is manifestly impossible to predict 

the probable shape and size of ore bodies formed in this manner. 

The roscoelite seen near Placerville appears, however, to be much 

more persistent than the carnotite. There is no apparent reason why 

a mass of sandstone, impregnated with roscoelite, which is continuously exposed for several hundred feet along a cliff, should not extend 

for a considerable distance inward from the cliff face. The carnotite, 

on the other hand, appears,to be of much more superficial occurrence, 

and its connection with the present surface of the ground is not yet 

fully understood. This would indicate that the carnotite results from 

a local concentration of material already existent in the sandstone, and 

the deposition of this material in the form of carnotite under conditions determined by proximity to the surface, and probably 

dependent upon a semiarid climate.

a Am. Jour. Sci., 4th ser., vol. 6, 1898, pp. 209-216. 

Bull. 262 05 2
18 ' CONTRIBUTIONS TO MINEEALOGY. [BULL. 262.

CHEMICAL ANALYSES AND DISCUSSION.

By W. F. HILLEBRAND. 

I. GREEN COLORING CONSTITUENT OF PLACERVILLE SANDSTONE.

As noted by Doctor Ransome, the greener the sandstone the greater 

has been the replacement of the calcareous cementing material by the 

ciystalline vanadiferous mineral. Fortunately, the greenest available 

specimen was entirely free from carbonate, and this was used for 

analysis, 10 grams being taken for the main portion.

The green substance was but slightly attacked by cold acids and not 

rapidly by hot ones, nevertheless after from twelve to twenty-four 

hours' digestion on the water bath with diluted nitric acid the greenish 

color had been transferred to the liquid, the residue of sand was nearly 

white, and a rather voluminous separation of nongelatinous silica had 

taken place. The filtration and washing of the insoluble matter was 

accomplished without difficulty. The free silica in it was extracted by 

two or three digestions of fifteen minutes each on the water bath with 

sodium carbonate solution of 5 per cent strength. The flocculent matter 

had entirely disappeared and the sand}^ residue was collected in a Gooch 

crucible and washed with hot sodium carbonate solution, followed by 

very dilute nitric acid, and finally by alcohol, to prevent turbid filtration. Drying of the sand was effected by allowing the pump to draw 

air through the crucible until no further loss in weight resulted.

The water in the sand was then determined at 105°, at 300°, and 

above 300°. Similar water determinations having been made on the 

unattacked substance, the differences gave the water expelled at those 

temperatures from the soluble part.

The sodium carbonate solution was acidified, evaporated, and filtered, and the filtrate again evaporated, to recover the last of the silica. 

To this was added a very small portion which the nitric-acid extract 

of the sandstone held in solution. The sum represents the total silica 

of the decomposed portion of the sandstone.

The further analysis of the nitric solution presented difficulty 

because of the vanadium it contained. It was carried out in a variety 

of ways, of which the following seemed to be most satisfactory:

Barium was first precipitated by sulphuric acid and subsequently 

separated from traces of lead, calcium, and vanadium. Hydrogen 

sulphide then threw out further traces of lead and copper with much 

sulphur from reduction of V2O6 to V2O4 . After evaporation of the 

filtrate to reoxidize vanadium and iron, the alumina, iron, and trace 

of uranium with much vanadium were separted from the calcium, 

magnesium, and alkalies by three precipitations by ammonia solution. 

The combined filtrates were evaporated and ignited, the residue was 

transferred to a porcelain boat with nitric acid, evaporated therein to 

complete dry ness, and exposed in a glass tube to a current of dry
HILLEBRAND.] CARNOTITE AND ASSOCIATED MINEKALS. 19

h}^drochloric-acid gas, as recommended by Smith and Hibbs a for the 

expulsion of vanadium from alkaline vanadates. The removal of 

vanadium being incomplete, the contents of the boat were again 

evaporated with nitric acid and again .distilled, and these operations 

were repated till no further evidence of a brown distilate appeared. 

The boat now contained only magnesium and alkalies with a little 

calcium. The distillates, containing all the vanadium that was in the 

boat, had been collected in U-tubes charged with water, and were 

eventually obtained in sulphuric solution for further treatment by 

evaporating with sulphuric acid in porcelain.

The precipitate of A12O3 , etc., was dissolved in nitric acid, evaporated almost to dryness in platinum, and boiled with sodium-hydroxide solution. These operations were repeated on the precipitate after 

filtration. The iron and titanium thus purified were redissolved,' precipitated by ammonia, weighed, redissolved by acid potassium sulphate, 

and the ferric iron was reduced by hydrogen sulphide and titrated with 

permanganate after boiling out the reducing agent. The titanium 

was then found colorimetrically by hydrogen peroxide.

The combined alkaline filtrates were heated with excess of ammonium nitrate to separate alumina from most of the vanadium. The 

precipitate was redissolved in nitric acid, reprecipitated by ammonia, 

then ignited and weighed and redissolved by acid potassium sulphate. 

The sulphuric solution was reduced by'hydrogen sulphide, boiled and 

filtered from platinum sulphide, again boiled in a current of carbon 

dioxide, and titrated hot with permanganate. Sulphur dioxide gas was 

then introduced, boiled out in a current of carbon dioxide, and the 

titration repeated, this second result being taken as representing the 

V2 04 equivalent to the V2 05 that still contaminated the A12O3 . Deducting the V2O5 thus found from the combined weight of A12O3 and V2O5 

gave the A12 03 of the soluble constituent of the sandstone.

The combined filtrates from the alumina were evaporated and ignited 

to remove ammoniacal salts; the residue was converted to sulphates 

and united with the earlier solution of vanadium sulphate. The 

vanadium in it was then determined precisely in the manner already 

described, and when added to that found with the alumina and calculated to V2 03 gave the total in the sandstone.

A check was made by dissolving the sandstone in hydrofluoric and 

sulphuric acids in a current of carbon dioxide and titrating the V2 03 

with permanganate. The figure thus obtained was a trifle below that 

found as above detailed, and this is to be attributed to the presence of 

a very little vanadium as V2 05 in carnotite, and probably as a lead 

vanadate. All the uranium and most of the trifling amount of lead 

could be extracted by cold dilute nitric acid, showing that they were 

foreign to the green substance.

"Jour. Am. Chem. Soc., vol. 16,1894, p. 578.
20 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

It is preferable to regard iron as in the ferric rather than the ferrous state; otherwise an equivalent amount of vanadium would have 

to be considered as V2OB , for which there is no occasion. It is quite 

possible that the iron is in part, if not wholly, foreign to the green 

matter, for it would be surprising to find an exposed sandstone free 

from ferric oxide.

If the iron is disregarded as probably extraneous, the ratios given 

below afford the following empirical formula:

Ol7f.q Wo77K« '

TJ t>/ H-SM -".i

r *-QOfl J-V w-t Q,|

R'"

39 1X 610 R"39 R' (SiOJBM (SiA),

Simplified, this is Hi0 -R'20 R"4 R'"61 X62 . 4 .

In view of the fact that the mineral is probably not perfectly pure 

and of the uncertainties affecting the amount of water to be considered, 

etc., the above affords a close approach to the typical phengitic muscovite formula, H2KR'"3X3 , in which X comprises the groups Si04 

and Si3 0g .

Soluble in nitric acid: 

Si02 ......................

Ti02 ...... ................

v n

ALA-...--...-..---..-...

Fe,08 . ....................

CaO ......................

BaO ......................

MgO.. ....................

K2 0 ..............;.......

Na2 0 ..;....:.............

H26 at 105° ...............

H20 at 105°-300° ..........

H20 above 300° ...........

U03 . .....................

PbO. .....................

V2 05 . ....... ....°.. ........

Insoluble in nitric acid: 

Quartz, etc .................

H20 at 105° ...............

. H2 0 above 105° ...........

Sandstone.

12.56'

.02

«3.50

6.15

.20

.12

.37

.25

2.41

.06

.54

.14

.97

.05

.06

.05

6 72. 24

.04

.20

99. 93

Ratios.

.0. 763

0846U 

M). 305 

. 2206/

.0046

. 0078] 

. 0088 . 039

. . 0228

. . 0938;

\ .097 

. 0035/

.1100

.0283

. 1978 .198

Silicate.

46.06

f 12. 84

I 22. 55

.73

( .44

1.35

I .92

f' 8. 84

I .22

1.98

.51

3.56

100. 00

Roscoelite.

45. 17

.78

24.01

11. 54

FeO 1. 60

1. 64

10.37

.06

.'40

.17

4.12

99.86

a Oxidation by permanganate of the HF1 and H»S04 solution of the sandstone indicated 3.43 per 

cent V203 (mean of 3.50, 3.32, 3.48, 3.43).

b Containing about 65 per cent Si02 , 7 per cent A120S (Feo03TiOj.) and about 0.3 per cent of zircon 

and other minerals not decomposed by repeated evaporations with HF1 and H2S04.

Traces of Li, Cu, Mo, Bi. No 01, S03 , or P2 05 .
HIM.KBRAND.] CAENOTITE AND ASSOCIATED MINEEALS. 21

An attempt to satisfactorily distribute the constituents among different chemical molecules would be futile, since, for instance, we do not 

know whether to ascribe the barium to a biotite or muscovite molecule, 

but the dose approach to the muscovite ratio leaves little room to 

doubt the character of the body. Notwithstanding the chloritic aspect 

of the mineral Under the. microscope, the analysis shows that it can not 

be a chlorite, and we have undoubtedly to do with a body closely 

related to the mica roscoelite, wherein, however, the percentage proportions of A12 0S and V2 03 are reversed, thus affording a further 

striking example of the mutual replaceability of these two oxides.

For comparison, the latest analysis of roscoelite from Placerville, 

Cal., is included in the above table. Peculiar, though unimportant, 

is the coincidence that the only two known localities for this mineral 

should bear the name Placerville.

II. GREEN SANDSTONE COLORED BY CHROMIUM.

Other sandstones that were a much brighter green than the vanacliferous one were observed and collected by Doctor Ransome, both 

at Placerville and 60 miles distant in Sin bad Valley. The color suggested a .salt of copper as its cause, but analysis showed it to be due 

to chromium. Time has not been found to determine the nature of 

this coloring body. It is very difficultly soluble, and thus presents 

greater hindrance to analysis than did the vanadium compound. It 

would be interesting to find that it is a micaceous mineral analogous 

to the one just described. Under the microscope it presents a chloritic appearance (Ransome). If opportunity offers, the problem of its 

nature may yet be attacked.

In still another greenish sandstone from the west bank of the 

Dolores River, near the mouth of La Sal Creek, analysis failed to 

show either vanadium or chromium.

III. CARNOTITE ORES. 

OPTICAL EXAMINATION.

Dr. George P. Merrill has kindly submitted the following notes: 

The carnotite powder appears under the microscope in the form of exceedingly 

minute dust-like particles without crystal outlines and acting so faintly on polarized 

light as to at first seem almost amorphous. Much of the matter appears merely as 

a fine brownish clay, stained yellow by an amorphous pigment, but occasionally a 

well-defined fragment of a light-yellow translucent mineral is seen, which doubtless 

represents the vanadium compound in its condition of ideal purity.

Working over a considerable amount of the powder I have found occasional clusters of this yellow mineral in the form of flattened radiating crystals with pyramidal terminations which are without evident pleochroism, polarize only in dull 

colors, and give extinctions always parallel to the axis of elongation. These are so 

minute (not over 0.25 mm. in length) and so thin that I. have never been able to 

find a crystal so oriented as to give an opportunity of determining its exact character, and I can only say that the general shape is such as to suggest a hexagonal 

mineral, though this is by no means certain. . «
22 CONTRIBUTIONS TO MINERALOGY. [BULL.262. 

CHEMICAL EXAMINATION OF CAKNOTITE ORES.

The chemical problems involved in the analysis of the carnotite ores 

were peculiarly intricate. Ideal material was quite unobtainable and 

mechanical separation was impossible. The first specimen received 

happened to be of higher grade than any of the subsequent ones, containing about 5 per cent of sand grains and showing only very faint 

delicate reddish tracings, indicative of some foreign iron mineral. In 

mass it was of a beautiful canary-yellow color and easily broken 

down by pressure. Other specimens were more coherent, the degree 

depending altogether on the extent to which the sandstone had been 

impregnated and altered, and they sometimes showed more of the 

peculiar reddish admixture.

A fact only suspected in making the first analysis was confirmed by 

subsequent work on lower-grade ores, namely, that the vanadium existed 

in two conditions, in entirely distinct minerals, the greater part by far 

as pentavalent vanadium in the easily soluble carnotite, and a smaller, 

much less soluble portion, almost vanishing in the purest ores, in the 

trivalent state as a constituent of a silicate free from uranium. This 

observation explained the statement of Messrs. Poulot and Voilleque 

that they had found the low-grade ores relatively richer in vanadium, 

as compared with uranium, than the high-grade ores.

While the carnotite dissolves at once in cold dilute nitric acid, 

unfortunately the vanadiferous silicate is not quite insoluble, hence 

arose an important difficulty in the way of arriving at the true composition of the carnotite. It is true that in one case the silicate has 

been analyzed (p. 30), but it would be unsafe to correct the carnotite 

analysis on that basis. Moreover, the analyses were not all made on 

the same plan; some are less complete than others; they can not in 

some respects be rigidly compared with one another.

As to the carrying out of the analysis, various procedures were 

tried and no one was found which gave altogether satisfactory results 

as to each constituent, though many could be determined with the 

usual degree of accuracy. The difficulty was due mainly to vanadium 

and the small amount of phosphoric acid usually present. These two 

constituents were likely to be found in different precipitates and could 

not be separated from them at one stroke. Their complete removal 

from other bodies was at times impossible, and the weight of the latter 

had then to be corrected for these residual amounts.

Two entirely different lines of attack were open. One, that of 

Friedel 'and Cumenge, described in their paper on carnotite, had 

alread}' been used with apparent success. It depends on rendering 

the vanadium insoluble in water by evaporating the nitric acid solution to dryness. Water extracts the alkalies and uranium without
HIU.EBRAND.] CARNOTITE AND ASSOCIATED MHSTEKALS. 23

dissolving the vanadium, iron, or aluminum. Repetition of this proc 

ess yielded Friedel and Cumenge satisfactory results. They recommended washing with water containing ammonium nitrate.

The other method involved the quantitative removal of vanadium by 

dry hydrochloric acid gas in the manner already described (pp. 18-19). 

Smith and Hibbs had shown that this method is perfect for alkaline 

pyrovanadates and it was hoped that it might succeed even with such 

complex mixtures as those under consideration. The distillations were 

made on the crude ore and also on the nitric acid solution after filtration from the insoluble matter and evaporation to thorough dry ness. 

The action is immediate in the cold, copious red-brown vapors coming 

off and condensing in part as a dark red liquid in the tube. But 

repeated distillations and the application of heat were required to 

effect complete removal of the vanadium accompanied by the arsenic 

and molybdenum. After each distillation the contents of the boat had 

to be evaporated with nitric acid. The blue and green colorations 

apparent on adding this acid showed that the hydrochloric acid gas 

had reduced a good deal of the vanadium to a lower state of valence, 

and in this condition it was incapable of forming the volatile body.

A somewhat more satisfactory separation sometimes resulted when 

this distillation method was combined with that of Friedel and Cumenge 

by subjecting both the evaporated uranium nitrate solution and the 

residue insoluble in water to the action of hydrochloric acid gas.

The distillates obtained by either way were evaporated with sulphuric 

acid, the arsenic and molybdenum were separated by hydrogen sulphide, and the vanadium was then titrated by, permanganate at a temperature near boiling and again after reduction Iry sulphur dioxide 

gas. In one or two cases when the temperature of distillation had 

been high and it was feared some iron had passed over, the distillates 

were evaporated in porcelain with nitric acid, transferred to a platinum 

crucible, evaporated therein with sulphuric acid, and fused with sodium 

carbonate. The aqueous extract was then treated as above for arsenic, 

molybdenum, and vanadium.

The mode of separation practiced by Friedel and Cumenge, while 

perhaps adequate for technical purposes in ores free from phosphorus/' 

does not in my hands give perfect satisfaction even then. It is impossible to prevent a little of the vanadium, also of the iron and aluminum, from going with the uranium, and on the other hand a little 

uranium may stay with the vanadium. Again when the vanadic acid

a With even only half a per cent of P205 many times that amount of U03 is rendered insoluble in 

water after evaporation to dryness with nitric acid. The compound formed is of a.lemon-yellow color, 

which is masked by the separated vanadic acid until this has'been removed by ammonia. This 

insoluble body was treated as follows in order to arrive at the P.205 and U0: , it contained. After 

solution in nitrite acid the phosphorus was precipitated by ammonium molybdate, and from the 

nitrate the uranium by three precipitations by ammonia.
24 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

is extracted from the residue by ammonia, as prescribed by Friedel 

and Cumenge, a little of the other constituents of the residue accompany the vanadium into solution.

If the combination of the two methods is used, it is better, after the 

vanadium has been removed by distillation, to treat the two residues 

separately at first instead of to unite them at once. Full details of 

this treatment are unnecessary and would unduly extend this paper. 

Suffice it to say that from the uranium portion the little iron and 

aluminum present are separated by ammonium sulphide and carbonate, and after removal of the latter and acidification the uranium can 

be thrown down by ammonium sulphide, and then by at least two 

precipitations by ammonia, or far better, b}^ precipitating the neutral 

hydrochloric solution by freshly precipitated and alkali-free mercuric 

oxide at boiling heat, as prescribed by Alibegoff. a As pointed out by 

von Foullon and also by Alibegoff, contrary to certain still widety disseminated statements, ammonium sulphide does not afford a good separation of uranium from calcium. This is perhaps especially true if the 

solution contains any phosphorus. Again, contrary'to another statement, it seems perfectly possible to separate uranium completely 

from alkalies by a few ammonia precipitations.

The finally ignited and weighed U3 0g was redissolved in nitric acid, 

filtered1, if necessary (Si02 , A13 03 , Fe8O3 ), and divided into two parts, 

one of which was tested for the very little P2O5 usually present, and 

the other for vanadium by conversion into sulphate, reduction by sulphur dioxide gas, and titration by very dilute permanganate solution.

ANALYSES OP CAKNOTITE ORES.

I. Copper Prince claim, Roc Creek, Montrose County, Colo.

According to the donor of the specimen, Mr. J. K. Duling, l-a is 

from the same lot as that from which Mr. Poulot obtained the specimens afterwards analyzed by Friedel and Cumenge.

II. Yellow Boy claim, La Sal Creek, Montrose County, Colo.

III. Yellow Bird claim, La Sal Creek, Montrose County, Colo.

The last two claims belong to the same group and the ore is from 

the same "blanket" (Voilleque).

1-J and II-5, the first analyses made, are not strictly comparable 

with the other analyses, since they represent the effect of warm dilute 

hydrochloric acid, whose greater action is, shown by the nearly complete solution of the ferruginous admixture. Cold, dilute nitric acid 

was used for the other analyses.

a Ann. Chem. u. Pbar., vol. 233,1886, p. 133; Zeit fur anal. Chemie, vol. 26,1887, p. 632.
HILLEBRAN1X] CAENOTITE AND ASSOCIATED MINEEALS. 25

Insoluble..........

UO..... ...........

V O

P205 ........ ......

As20s .............

A120, .............

Fe20;, .............

CaO...............

SrO ...............

BaO ..............

MgO ..............

K20... '............

NajO..............

Li20 ..............

H2 0 at 105° .......

H2 0 at 350° .......

H2 0 above 350°....

PbO ..............

CuO ..............

so,.....;-.........

MoOH ...\.........

SiOa .. .............

Ti02 ..............

C02 . ..............

a.

«7.10

54.89

18. 49

.80

trace

.09

.21

3.34

.02

.90

.22

6.52'

.14

trace

2.43

2.11

none

.13

.15

.18

.15

.03

.56

98.46

I.

b.

&S.34'

52.25

18.35

.35

 .25

(?)

1.77

2.85

(?)

.72

.20

6.73

.09

(?)

2.59

3.06

none

.25

.20

.12

.23

.06

.10

.33

98.84

c.

c 19. 00

47. 42

15.76

.40

none

.08

.72

2.57

(?) '

.65

.24

6.57

.07

(?)

1.85

2.79

none

.18

.22

.18

.18

.13

(?) '

99.01

I

a.

rflO.33

54.00

18.05

.05

none

.29

.42

1.86

trace

2.83

.14

5.46

.13

trace

3.16

2.21

none

.07

trace

.05

.20

(?)

99.25

r.

b.

( e )

52! 28

17.50

trace

none

(?)

3.36

1.85

trace

3.21

:n

5.11

.02?

(?)

4.52

3.49

in.

(/)

20.51

7.20

none

none

.08?

.25

1. 64

(?)

.29

.07

1.51

.01

(?)

1.85

f/1.64

A. 19

.09

trace

.04

.07

-.06?

« Containing 0.54 HoO, 0.09 V»03. &The insoluble matter had "the following composition: Si02, 5.18; VoOs, 0.21; -P206 , 0.09; KoO, 0.2G; 

Na2 0, 0.04; H2 0,105°, 0.50, 350°, 0.32, +350°, 0.48; A1203 , Ti02 , Cr?03 , etc.,"by diff., 1.20. The S0;t of this 

ore is not combined with BaO, for it is wholly extracted by dilute acids. Once in solution the acid 

used is sufficient to prevent its immediate precipitation as BaSO< by union with some of the barium 

present. The same holds true for the S03 of I-c.

c This material was obtained by floating off the finer matter, .allowing it to settle, collecting on a 

Gooch filter, and drying it in a current of air drawn through the crucible. The insoluble matter held 

in addition to 16.41 quartz and silicates (including 0.39 V»03 and a little U03 ), H20,105°, 0.83; 300°, 

0.73; +300°, 1.03; total HnQ, 2.59.

d Containing 0.10 Vo03 and 1.90 H20.

e'Phe insoluble matter contained besides quartz and silicates: 0.25 V:>03, 0.21 K3O, 0.05 Na«0.

/This analysis was made purposely on a relatively poor ore, furnished by Messrs. Poulot and Voilleque, with the object of determining, if possible, the composition of the vanadiferous silicate which 

it contained (see p. 30). The data for calculating the H20 values of both analyses are as follows:

H2o at 105° .:...................................................

H20 at 300° ......................................................

Ore.

(a) 

3.53

2.11

.83

6.47

After extraction of carnotite by cold, 

dilute nitric 

acid.

(b) 

1.68

.47

.64

2.79

After extraction of residue by hot 

nitric acid, 

sodium carbonate, etc. 

(c) 

0.02

.03

.02

.07

a-6 furnishes the values for the carnotite as shown in analysis III; b-c gives those for the less soluble silicate (p. 30). 

0 At 300°. 

A Above 300°.
26 CONTRIBUTIONS TO MINERALOGY. [BULL. 262. 

DISCUSSION OF THE CAKNOTITE ANALYSES.

( It will be noted that a somewhat marked deficiency appears in most 

of the analyses, the cause of which is quite unknown. Great care was 

exercised in most cases and especially in those which show the greatest 

loss. It seems hardly possible that any serious constant loss of a 

known constituent should have occurred, but the only alternative 

demands the presence of an element or elements unnoticed and which 

can not have been weighed with the known constituents. The 

researches of M. and Mme. Curie have shown that these ores contain 

traces of radio-active elements, precipitated the one by hydrogen 

sulphide, the other by sulphuric acid. Their presence, however, in 

quantity sufficient to account for the observed losses in the above 

analyses, especially when 10 grams of ore were operated on, could not 

possibly have escaped observation. To whatever cause it may be due, 

this loss alone suffices to render somewhat uncertain any calculations 

based on the analytical figures, though if the loss is to be ascribed to 

uranium or vanadium the ratios would not be sufficiently affected to 

obscure any simple relations that might exist." ^

Another difficulty is the impossibility of knowing what constituents 

to exclude and what to include in deducing molecular ratios. It is 

certain that most if not all of the iron is foreign to the yellow body. 

It is probable that phosphorus is likewise so, since its extraction by 

dilute acids does not keep pace with that of the uranium and vanadium. 

It may possibly be in combination with the iron, in part at least. The 

alumina doubtless is derived from the vanadiferous silicate which 

seems to exist in all the ores and which is not quite insoluble in cold 

dilute acids. If so, a small portion of the vanadium, potassium, magnesium, and water are to be attributed to this mineral, but a general 

correction based on the analysis of this compound (see p. 30) would 

not be justifiable. Its application leads to nothing definite, even in 

the case of the particular ore No. Ill, from which the silicate analyzed 

was derived.

In the following tables are given first the recalculated analyses and 

then the molecular ratios. All those constituents have been excluded 

which pretty certainly do not belong to the carnotite, but small portions 

of some of those retained are unquestionably extraneous. In two cases 

(I-a and I-J) a certain proportion of lime has been arbitrarily excluded 

equivalent to the acid anhydrides CO2 , MoO3 , and S03 , less what is 

needed to offset PbO and CuO.

"According to Dr. Harry C. Jones, of Johns Hopkins University, who very kindly undertook to 

examine a specimen of the Copper Prince ore fqr rare gaseous elements, helium is not present. 

Faint hydrogen lines were observed, the source of which was ascribed to water vapor. Other lines, 

due probably to hydrocarbons, were fairly strong, but the specimen had been long enough exposed 

in our laboratory and elsewhere to have accumulated enough dust to account for them.
HIUJ2BKAND.] C ARNOTITE AND ASSOCIATED MINERALS. 

CARNOTITE ANALYSES RECALCULATED.

27

V O

P O

As205 ......:....

U08 ............

CaO ............

BaO(SrO).......

MgO ............

K,0 .............

Na20 ...........

H,0-105° ......

H20-|-1050 ......

' I-a.

20.72

.90

61.53

3.03

1.03

.25

7.31

. .15

2.72

2.36

100. 00

1-6.

21.09

.40

.29

60.06

2.77

.83

.23

7.73

.10

2.98

3.52

100. 00

I-C.

20.12

" .51

60.55

3.28

.83

.31

S..39

.09

2.36

3.56.

100. 00

II-a.

20.54

.06

61.44

2.11

3. 22

.16

6.21

.15

3.59

2.52

100. 00

II-6.

19.85

59. 31

2.10

3.64

.19

5.80

.02

5.13

3.96

100. 00

:ui.

20.62

58. 75

4.70

.83

.20

4.33

.03

5.30

5.24

100. 00

MOLECULAR RATIOS.

V205 ------------

p n

As2 0f) ...........

uo, ............

CaO ............

BaO(SrO).......

MgO... .........

K2 0 ............

Na,0 ...........

HaO-105° ......

I-L.O-l-1050 ......

1133 

63

541' 

68 

62. 

776) 

33J

1196 

2140 

h 671

> 809

1511 

1311

1208' 

28 

12.

' 495' 

54 

57. 

f 826-) 

I 22)

1248 

2088 

606

> 848

1656 

1956

1101:

36

f 586' 

54 

I 78.

/ 8911 

1 20J

1137 

2105 

718

> 911

1311

1978

[1124

I-4.

377" 

210 

40 

f 659] 

1 33J

 1128 

2136 

627

 692

1994 

1400

f 1081

1

2062 f376 !

238 660

I 47J 

( 616) { J 020

2850 

2200

1128

839 

54 

50 

f 460] 

I 6J

2043 

943

 466

2944 

2911

These ratios lead to the following empirical formulas, in which only 

the water given off above 105° is considered. Since the water is 

wholly removable below 350° it is regarded as water of crystallization 

and not of- constitution.

I-a .............

1-6 .............

I-c

II-a ............

ll-b ............

Ill .............

R'.-

1618

1696

1822

1384

1240

932

R".

671

606

718

627

660

943

Rv.

2392

2496

2274

2256

 2162

2256

U.

2140

2088

2105

2136

 2062

2043

0.

13880

13958

13629

13367

12871

13178

H2 0.

1311

1956

1978

1400

2200

2911
28 CONTRIBUTIONS TO MINERALOGY. [BULfc..262.

If it be assumed that the bivalent elements offer the most accurate 

determinations, the above ratios may be reduced to the following 

simpler terms on that basis:

I-o .............

1-6 .............

I-c .............

II-ci ............

II-6 ............

Ill .............

R'.

2.41

2.80

2.54

2.21

^88

.99

R". -

1

1

1

1

1

1

Rv -

3.56

4 19

 3.17

3.60

3 27

2.39

u.

3.19

3.45

2. 93

3. 41

3.12

2.16

0.

20.68

23. 03

18. 98 '

21. 32

19.50

13.98

HoO.

1. 95

3. 23

 2.75

2.23

3.33

3.09

The results, however, show a great lack of agreement and wide 

variation. It is plain that no probable formula can be calculated for 

the yellow body. The variations are of such a nature as to indicate 

in the plainest manner that it is a mixture of several substances.

So detailed a discussion as the foregoing would hardly have been 

justified, in view of the negative conclusions arrived at, but for the 

fact that Messrs. Friedel and Cumenge in their paper announced a 

simple formula for the body examined by them and gave it the specific 

name carnotite. Their published analyses are as given below, from 

which they have excluded considerable sand and traces of barium, 

aluminum, lead, copper, and radio-active bodies as present in excessively small quantities. They make no mention of calcium and admit 

that their values for water are open to doubt. The formula deduced 

by them is .2U8Os, a V2 05 , KA 3H2 0.

U 0 «

V 0:

K,0. ......................

H2 0. ......................

Found.

1.

64.70 

20. 31 

10.97

.96

2.

62.46 

19. 95 

11. 09

.65

3.

5.29

4.

4.81

Calculated.

63.54 

20. ] 2 

10.37 

5.95

99.98

a Old notation, equivalent to the-modern U03 .

It appears from these analyses that Messrs. Friedel and Cumenge by 

great good fortune obtained a variety of samples of the pure potassium 

compound, free from calcium and without appreciable admixture of
HILLEBRAND.] CARNOTITE AND ASSOCIATED MINERALS. 29

barium. This is very remarkable in view of the fact that all the ores 

from different localities, examined by me show large admixture of 

calcium or barium salts or both, even that which is certified to have 

come from the same lot as that from which their material was taken. 

The French authors give a brief outline of their methods of analysis. 

That one which afforded them the best results would involve the 

weighing of any calcium present as sulphate along with the potassium, 

on the assumption that the presence of that element had been overlooked. It is much to be desired that a reanalysis of their material 

should be made, if there is any of it still available, in order to clear 

up the doubt connected with the first analysis.

In the light of the evidence herein set forth, the existence of a distinct mineral species having the composition claimed for carnotite can 

by no means be considered as established. '

AVERAGE QUALITY OF MARKETED ORE.

As these carnotite ore bodies are being exploited for the market, it 

is of some interest to know the average quality of each commercial 

lot. A carefully prepared sample representing several tons of .ore was 

received from one of the commercial houses of Denver and was found 

to carry 11.49 per cent of uranium counted as U3 0g , and 6.40 per cent 

of vanadium counted as V2 05 . Over one-sixth of the vanadium existed, 

however, in thetrivalent state, not as a constituent of the yellow body, 

but doubtless of a silicate like the one whose composition is given on 

page 30.

COMMERCIAL ASSAY.

The commercial assay of these ores has presented difficulties to the 

technical chemist, the results being sometimes very discordant.

As to uranium, this is not surprising. The methods that have probably been commonly employed will give varying results, according to 

the contents of the ore in phosphorus and alkaline earths. Possibly 

the old Patera process, described in most text-books on analytical 

chemistry, might be made to serve, with modifications called for by 

the large amount of vanadium present.

The assay for vanadium presents little difficulty and does not require 

much time. The ore is fused with sodium carbonate, leached with 

water, and the fusion repeated on the residue. The combined filtrates 

are acidified by sulphuric acid, arsenic and molybdenum are precipitated in the hot solution by hydrogen sulphide, whereby the V2 05 is 

reduced to V2O4 . After filtration and expulsion of hydrogen sulphide 

by boiling, the vanadium is titrated in hot solution by permanganate. 

It is then reduced by sulphur dioxide gas, and after boiling this out 

the titration is repeated. The results are exact, and they are not 

affected by the uranium that may be present.
30 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

IV. COMPOSITION OF VANADIFEROUS SILICATE IN CARNOTITE

ORE.

As already mentioned, the ores contain a vanadiferous silicate free 

from uranium. To the end of ascertaining its composition, if possible, 

ore No. Ill (p. 25), from the Yellow Bird claim, low in carnotite, but 

relatively rich in vanadium, was treated as follows:

The carnotite from 10 grams was extracted by cold, dilute nitric acid, 

and the well-washed residue, consisting of coarse sand and an utterly 

amorphous mud, by 4 per cent sodium carbonate solution to get rid of 

the small amount of silica presumably set free, but not dissolved by the 

acid. This amounted to 0.35 per cent in duplicate determinations, and 

together with 0.06 per cent in the acid solution, or 0.41 per cent in all, 

may serve as a maximum figure by which to gage the action of the 

cold acid on the silicate or silicates in the ore. The residue was then 

digested for several hours with warm nitric acid of about 1.2 specific 

gravity until, as shown by a companion test, its action had ceased. It 

was then filtered, washed, and digested with 5 per cent sodium carbonate solution to dissolve the copious deposit of silica. The final 

residue was collected in a Gooch crucible, washed with sodium carbonate, followed by dilute nitric acid to remove all alkali, then by 

alcohol to prevent turbidit)^ in the filtrate, and dried by suction of the 

pump. In it the water was determined at different temperatures; also 

its general composition. a From the sodium carbonate filtrate the 

silica was obtained by two evaporations and nitrations; also the trifling 

amount held by the acid solution. This latter was then fully analyzed 

and the complete results follow:

Si02 . ...... ..........i. .....................

A1 203 - --------------------------------------

VA- - --- - -.

Fe A ......................................

CaO..... ...................................

MgO.......................................

K2 0. ---------------------- .................

Na2 0. ---------- --------------------- :......

H20 at 105° C............ ...................

H2 0 at 300° C............ ...................

H20 above 300° C... ........................

Per cent in 

ore.

6.48 

b 2. 445 

c.965 

a . 875 

.035 

e.654 

.546 

.03 

/I. 66 

/.44 

/.62

14.75

Per cent calculated to 

100.

43.94 

16.58 

6.54 

5.93 

.24 

4.43 

3.70 

.20 

11.26 

2.98 

4.20

100.00

Ratios.

0. 1622 

.0434 

. 0370 

. 0043] 

. 1099J 

. 0393] 

. 0037J

0. 7275 

.2426

' . 1142

> . 0430

.9222 

.1655 

.2333

"SiOo, 48.89; ALO3 , Fe,03, zircon, etc., 0.44; Ti02 , 0.08, MgO, 0.01; K-O, 0.11; Na.,0, 0.03; H.,O, 0.07; 

total, 49.63. '>2."45and~2.44. cQ.93 and 1.00. <* 0.87 and 0.88. e07652 and 0.657. /Determined 

on a separate portion of the same powdered sample. See p. 25, footnote, for data.

Also traces of titanium, manganese, and lithium.
HILLBBBAND.] CARNOTITE AND ASSOCIATED MINERALS. ' 31

On the improbable assumption that the iron is to-be wholly included, 

and regarding only the water given off above 300°, the following 

ratios result:

1-1 T?' T?" T?''' ^i O X1 il>7 AV 80 iXl 114 "" 485 ^"727 W2573 J

which become, if the iron is excluded,

TT 

-n4G7 T?' "SO " T?" 114 T?'" " 411 °m J 727' VO^240a t

These figures, while strongly suggesting definite ratios between 

certain of the constituents, do not under the circumstances warrant 

the deduction of a formula, nor do they lead to the same conclusion as 

in the case of the green cementing material of the sandstone at Placerville. The phengite-muscovite ratio of that is not apparent here; 

yet it is not at all unlikely that a mineral like the one from Placerville 

is present, but contaminated with some other. In fact it would be surprising to find anything but a mixture in sandstones so thoroughly 

altered. The very existence of such vanadiferous transition products 

is itself highly interesting, and these tedious analyses were not therefore made in vain. The mud-like amorphous character of this material 

precludes any hope of aid from the microscope in solving the question 

of its homogeneity.

SUMMARY.

The. body -called carnotite is probably a mixture of minerals, the 

exact nature of which analysis fails to reveal. Instead of being the 

pure uranyl-potassium vanadate, it is to a large extent made up of 

calcium and barium compounds. Intimately mixed with and entirely 

obscured b}^ it is an amorphous substance a silicate or mixture of 

silicates containing vanadium.in the trivalent state probably replac- 

.ing aluminum.

The deposits of carnotite, though distributed over a wide area of 

country, are for the most part, if not altogether, very superficial in 

character and of recent origin.

The green coloring and cementing material of certain sandstones 

near Placerville, Colo., is a cryptocrystalline alumino-vanadio-potassium silicate resembling roscoelite, but with the, percentage proportions of A12 03 and V2O;, reversed. It constitutes over 25 per cent of 

portions of the sandstone, and contains nearly 13 per cent of V2O3 , the 

latter amounting in the maximum case observed to 3.5 per cent of the 

sandstone.,

As yet (1900) these, highly vanadiferous sandstones have been found 

only at Placerville, where it is intended to work them for vanadium. 

Carnotite is associated with them in only trifling amount.

Other sandstones noticed owe their bright green color to chromium.

In yet another case where the color was dull green this was not due 

to either chromium or vanadium.
SOME ADDITIONS TO THE ALUNITE-JAROSITE GROUP OF

MINERALS.

By'W. F. HILLEBRAND and S. L. PENFIELD.

Two new varieties of jarosite will be described in the present paper. 

One is from Nevada, and was collected by Mr. H. W. Turner, of 

the United States Geological Survey, and sent to the Survey laboratory at Washington for identification; the other is from New Mexico, 

and was sent by Mr. J. H. Porter, of Denver, Colo., to the min 

eralogical laboratory, of the Sheffield Scientific School. Except for 

slight differences in color the two minerals look exactly alike, each

consisting of minute, isolated, tabular crystals, which, as may be seen with the microscope, are composed of combinations of a 

rhombohedron with largely developed basal 

planes. By chance it happened that the 

present writers discovered that they were 

both engaged in the investigation of compounds belonging evidently to the same 

group, and it was decided to bring the 

results together into one paper.

NATROJAROSITE.

The material collected by Mr. Turner was 

obtained on the east side of Soda Springs 

Valley, Nevada, on the road from Sodavttle 

to the Vulcan copper mine. It consists of 

a glistening powder, made up of perfect 

crystals having the habit shown in fig. 1, although generally only 

one rhombohedron, r, is present instead of two, as shown in the figure. 

The largest crystals observed were 0.15 mm. wide and 0.025 mm. 

thick, and the general average would not be over half that size. In 

spite of their minuteness, however, it was possible to measure the 

angles of the crystals with the reflection goniometer, the chief difficulty arising not so much from their small size as from the vicinal 

character of the basal planes. After repeated trials a crystal was 

32

FIG. 1. Natrojarosite.
.LEBRAND 

AND PEN FIELD. ADDITIONS TO THE ALUNITE-JAEOSITE GKOUP.

found having a fairly good basal plane, and from this crystal the following angles were obtained:

CalcuMcasured. Measured. lated.

c^r, 0001/aOll-=51° 53'-* c^s, 0001^0221=68° 42' 68° 35'

c/^r', 0001/^1101=51 53 c/oy , 000 1/^202 1=68 48 68 35

c^r", 0001^0111=52 '26 r/oy , 1011^1101=86 5 85 54

The crystals belonged to the rhombohedral division of the hexagonal system, and the angle c /\ r, 51° 53', which is probably very 

nearly correct, has been assumed as fundamental, and from it the 

followin axial ratio has been calculated:

That the axial ratio as given is very near the truth is shown by the 

fact that the measurements of c ^ s and r ^ r do not vary many minutes from the calculated values; while on a number, of other crystals, 

measurement of the angle c ^ r, though varying considerably, was 

found to be not far from 52°. The angles of c ^ r and r ^ r' of the 

ordinary potassium jarosite are 55° 16' and 90° 45', respectively.

Under the microscope the crystals exhibit normal optical properties. 

With a high-power lens and convergent light the thicker crystals show 

the dark cross and the beginnings of the first ring of the interference 

figure. The birefringence is negative. The color of single crystals, 

when seen under the microscope in transmitted light, is golden yellow. 

Many of the crystals show numerous brown inclusions. The color 

shown by a mass of the crystals is yellowish brown, and the material 

glistens, owing to reflections from the basal planes of the minute 

crystals.

The material used for the chemical analysis was the purest that 

could be obtained, although crystals containing the brownish inclusions just mentioned could not be avoided, and there were occasional 

brown ferruginous particles mixed with the crystals. The specific 

gravity of the material was found to be 3.18 at 30.5° C, The results 

of the analysis by Hillebrand are as follows:

Ratio.

FeaO»...... ................................ 50.98 0.319 3.29

Na.,6 a................................... 6.03 .0941 ., Q1

Kj,0. ...... .............................. .35 " .004/

S0». .............. 1. ..-.--..-.....,.---.. 30.96 ' .,387 4.00

H,0 below 105° .......................... .12

H20 above 105° .......................... 11. 03 . 613

As A ..............:..................... .20

SiO,....-.....-..'.:..............'...---.. .23

CaO ..................................... .04

99. 94

«0f the soda 0.22 per cent is not extracted by hot water after full ignition of the mineral, and hence 

may belong to a feldspar or some other foreign mineral. Only 5.81 per cent is assumed to belong to 

the jarosite and vised in deriving the molecular value,

Bull. 262 05 3

\
34 CONTRIBUTIONS TO MINERALOGY. [BULL. 202.

The ratio of Fe2 03 : Na2O : SO3 : H2O is' evidently 3:1:4:6 as in 

ordinary jarosite, where the alkali is potash instead of soda. The 

slight excess of Fe2 03 and H2 0, as indicated by the ratio, is evidently 

due to some ferric hydroxide; probably the dark ferruginous impurities seen under the microscope are in part responsible for this, and 

there are also traces of some arsenate and silicate present. By attributing the excess of Fe2 03 and H2 0 to impurities, it is found that 94 per 

cent of the material analyzed may be regarded as pure natrojarosite, 

as indicated below:

Fe A .........................................

Na2 0 ..........................................

K2 0............... ..........................

S03 . ..........................................

H2 0.. ........................................

After deducting impurities.

46. 43 or 49.39

5. 81 or 6.18

. 35 or . 37

30. 96 or 32.94

10. 45 or 11. 12

94. 00 "or 100. 00

Theory for 

Na,FeB [OH],o 

~[S04] 4 .

49. 49

6.39

32.99

11. 13

100. 00

That 6 per cent of impurities should be present in a crystalline 

powder such as was analyzed is not surprising when it is taken into 

consideration that it would require something like 2,500,000 crystals 

to"-make one gram of material, the estimation being based on the 

assumption that the crystals are 0.10 mm. in axial diameter and 0.02 

mm. thick, which is certainly above their average size.

Among the specimens, from Cooks Peak, New Mexico, sent to the 

Sheffield laboratory by Mr. Porter, were some masses of a rather 

firmly cemented aggregate of minute crystals of a mineral of the jarosite group. The specimens are of a brownish-yellow color, and have 

in places the glistening appearance of a mica-schist. They also look 

as though they had been subjected to pressure and had been somewhat sheared. The material is rather easily crushed, and the powder, 

when examined with the microscope, exhibits the proprieties of the 

natrojarosite just described. The crystals are associated with a little 

limonite and quartz, and pure material for analysis could not be 

obtained. Only a partial analysis, therefore, was undertaken with 

the following results:

Fe203 ------------------------------------------------------- 55.60

Na.,6...............................I.....-....-.....-....--- 4.49

K2 0. ....................................................... .77

PbO................................................^........ .96

SO3 and H2O were present but not determined. The results are sufficient to indicate that the material is essentially natrojarosite.
ADDITIONS TO THE ALUNITE-JABOSITE GROUP. 35

PIAJMBOJAROSITE.

This material is from Cooks Peak, New Mexico. It occurs as a 

glistening, crystalline powder and as loosely cohering masses which 

may easily be crushed by pressure between the fingers. The crystals 

are very symmetrical, and are exactly like those of natrojarosite (fig. 

1), although generally only one rhoinbohedron, r, is present. On the 

average the crystals are a trifle smaller and noticeably thinner than 

those of natrojarosite. A number of crystals were measured on the 

reflecting goniometer, the chief difficulty arising rather from the 

vicinal character of the faces than from their small size. One 

unusually large crystal, 0.28 mm. broad and 0.015 mm. thick, was 

finally found, having the development shown in fig. 2, which is 

unusual, for general!}7 r (lOll) and not s (0221) is the prevailing rhombohedron. Fortunately the crystal was so taken up on a minute point 

of wax that the measurement of s^s in three 

rhombohedf al zones was possible. The results 

of five measurements of s s over the upper and 

lower pole edges varied between 109° 5' and 

109° 30', the average being 109° 16'; while

six measurements over the middle edges varied between 70° 10' and 

71° 00', the average being 70° 36'. The average of the two supplementary values gives s^s, 2201^0221 = 109° 20', which has been 

assumed as fundamental, and from it the following axial ratio has 

been calculated:

c=1.216.

On the crystal from which the foregoing measurements were obtained 

the basal plane was vicinal and hence no reliable measurements of 

c^s could be had from it. On a number of other crystals, however, 

the angle of c^r was measured with varying, results, the variation 

resulting f torn the uncertainty of the reflections from the basal planes. 

Four measurements of c^r, which were recorded in the notebook as 

derived fro'm the best reflections, varied between 54° 15' and 54° 44', 

the average being. 54° 30', while c/vr, 0001/vlOll, by calculation from 

the fundamental measurement, is 54° 32'. Hence it may be assumed 

that the axial ratio as established is reasonably exact. The calculated 

value of ?vr, 1011^1101, is 89° 42'.

In polarized light the crystals exhibit normal optical properties and . 

negative birefringence. Being on the average thinner than crystals of 

natrojarosite, it is seldom that, with the highest powers and convergent light, even the beginning of the first ring of the uniaxial interference figure is visible. Individual crystals show under the microscope in transmitted light a golden-yellow color. A mass of crystals 

has the appearance of a glistening dark-brown powder, the color being 

decidedly darker than that of natrojarosite*
36 CONTRIBUTIONS TO MINEKALOGY. [BULL. 262.

The analysis of the mineral was made on the very best material, 

having a specific gravity of 3.665 at 30° C. The results are surprising, 

and were wholly unlocked for, since it is found that this jarosite contains lead in the place of alkalies. The results by Hillebrand are as 

follows:

FeA ...............

AW -------------

PbO ................

K2O ................

Na2 0...... ..........

S03 .................

H20 below 105°......

H20 above 105°...-..

Si02 ................

CuO ................

CaO ............;...

Mgo..:. ...... .'......

I.

42.36

.12

19.69

.17

6.21

27.05

.02

9.59

..56

.27

.05

.01

II.

42.38

.08

19.99

27.07

9.49

.51

.27

ill.

0.11

19.89

.47

IV.

19. 79

^

Mean.

42.37

.10

19.84

.17

6. 21 .

27.06

.02

- 9.54

.51

.27

.05

.01

100. 15

Ratio.

0.265i

\ 3. 15 

.OOlJ

. 089 1. 05

.338 4.00

.530 6.27

.

"The presence of alumina was not definitely proved. The figures lierc given are the differences 

between, the several weights of the ammonia precipitates and those of the ferric iron in them, as 

determined by permanganate after reduction by hydrogen sulphide.

l> Probably somewhat high.

The ratio of Fe2 03 : PbO : SO3 : H2O is very close to 3 : 1 : 4 : 6, 

indicating that the mineral is a variety of jarosite, and. the slight 

excess of Fe2 0;j , H2 0^ and PbO + alkalies ma}^ be accounted for by 

assuming that slight impurities are present, partly ferric hydroxide, 

in part some lead salt, and perhaps a soluble silicate, as shown b}^ the 

complete solubilit}^ of .the silica in acids. Assuming that the ratio is 

exactly 3 : 1 : 4 : 6, it is found that 4.36 per cent of impurities are 

present, and the remaining 95.64 per cent may then be regarded as 

plumbojarosite, as follows:

Theory for PbFe0

IOH] IS [SO«] 4 . 

Fe203 .............................................. 40.59or 42.44

PbO .......:....................................... 18.86 or 19.72

S03 ................................................ 27.06 or 28. 29 . H,0...............--......:.............-.--....--- 9.13 or 9.55

95. 64 or 100. 00

Since it took probably 2,500,000 crystals of natrojarosite to make 1 

gram of material, it certainly must have taken fully 4,000,000 to make 

a gram of plumbojarosite, for the crystals of the latter mineral, 

though somewhat heavier, are decidedl}' thinner than those of the 

former; hence the presence of 4.5 per cent of impurities in such a 

crystalline product is not to be wondered at,
'HILLEBRAND 

AND PENFIELD,,] ADDITIONS TO THE ALUNITE-JAEOSITE GEOUP. 37

JAKOSITE AND AIAJNITE.

As may be seen from the- published analyses of these minerals, the 

alkali metal they contain is almost always potassium, though sodium is 

at times present. The formulas assigned to the two minerals are therefore K2O+3Fe2O3 +4SO3 +6H2O and K2O + 3A12 03 + 4S03 + 6H2 0, 

which may be variously expressed, as will be indicated later.

A mineral corresponding to natrojarosite of this article, though containing a little potash, has been described by W. P. Headden" from the 

Buxton mine, Lawrence County, S. Dak. The crystals are described 

as scales, consisting of a combination of base and rhombohedron. 

The material analyzed was evidently somewhat impure, as quartz 

and some As2 05 are reported. As the As2 05 evidently does not 

belong to jarosite, the assumption may be made that some scorodite, 

FeAs04 .2H2 0, is present, and the results of Headden's analysis may 

then be interpreted as follows:

FeA---------------. ------ 

NajO ............... ...........

K,0 ...........................

CaO ...........................

SO.............................

H2 0.... ..'.....................

As A ..........................

. Original 

analysis.

46.27

4.35

1.47

.39-

28.46

10.55

2.36

6.10

99.95

Scorodite 

and quartz.

1.60

.72

2. 36

6.10

10.78

Natrojarosite.

44. 67 or 50.10

4. 35 or 4. 86 .

1.47 or 1.65

. 39 or .44

28. 46 or 31.93

9.83or 11.02

89. 17 or 100. 00

Ratio.

3.13

1.04

4.00

6.13

Thus, assuming the presence of 4.68 per cent of scorodite and 6.10 

of quartz, and deducting them, the remainder agrees very closely with 

natrojarosite, giving a good ratio, very near 3:1:4:6.

Alunite containing considerable soda has been described by Whitman Cross 6 from Rosita Hills, Colorado, and by E. B. Hurlburt c from 

Red Mountain, Colorado, and analyses of both minerals show about 

equal percentages of K2O and Na2O, or a molecular ratio of 

K2 0: Na2 0=4:7. The occurrence, therefore, of sodium in the jarositealunite group is in accordance with previous observations, but the 

case is quite different with lead. As far as the present writers are 

aware, this is the first instance on record where lead has been observed 

isomorphous with the alkali naetals. It is interesting to note that the 

alunite from Red Mountain, Colorado, occurs as a crystalline powder, 

the crystals being exactty like those of natrojarosite and plumbojaroaAm. Jour. Sci., 3d ser., 46,1893, p. 24. blbid., 41, 1891, p. 472. dbid., 48, 1894, p. 130.
38 OONTEIBUTIONS TO MINERALOGY. [BULL; 262.

site, except that they are a trifle smaller and white, or colorless, when 

seen under the microscope.

From a chemical standpoint the most interesting feature of the new 

minerals is the light they throw upon the isomorphism of potassium, 

sodium, and lead. Ordinarily, even potassium and sodium are not 

isomorphous, as shown by the fact that their simple salts seldom 

crystallize in the same form. Although KC1 and NaCl both crystallize in cubes, it is not certain that both salts belong to the same group 

of the isometric system. It has been shown, for example, b}^ etching^ 

that KC1 crystallizes like NH4C1 in the plagihedral group of the isometric system, while the etchings produced on halite seem to indicate 

that it crystallizes in the normal group. Again, at Stassfurt, Germany, sylvite and halite both occur crystallized side by side upon the 

same hand specimen, instead of mixing as isomorphous molecules. 

Even in such complex molecular compounds as ,the feldspars, the 

potassium and sodium salts crystallize as orthoclase and albite, rather 

than as isomorphous mixtures. Lastly, potassium has a strong tendency to form alums, which is not shared by sodium. In contrast to 

these differences in chemical nature, we have in the jai'osite-alunite 

group of minerals not only the alkali-metals, potassium and sodium, 

but, what seems still more remarkable, lead, playing the :same rdle in 

the compounds, and yielding crystals which are. surprisingly alike in 

all their physical properties. The writers can at present offer no 

other reason for the isomorphism" in the group of minerals under consideration than that the alkalies and lead play so small a r61e, and the 

remaining constituents so prominent a part in the complex chemical 

molecules, that the latter control or dominate the crystallization by 

virtue of what may be called their mass effect. J w

The alunite from Red Mountain, described by Hurlburt, was analyzed in the Sheffield rnineralogical laboratory under the direction of 

one of the present writers, and it was found that water was first 

expelled from the compound at a rather high temperature, thus indicating that the mineral contains hydroxyl and no water of crystallization; accordingly it was shown that the seemingly complex formula 

of the mineral, expressed by the ration A12 03 : K2 0 : S03 : H2 0 = 3:1: 

4:6, may be much simplified to K[A1(OH)2 ]3 [S04]2 . In the light of 

the,present investigation it now seems best to abandon the above 

simple formula and adopt one containing double the number of atoms, 

in order to make clear the isomorphism between K2 , Na2 , and Pb. 

The formulas of the minerals of the group would then be expressed 

as follows:

Alunite .............................K2 [A1(OH) 2 ] 6 [S04] 4 or K2A16 [OH] 12 [S04 ] 4

Natroalunite....................... .Na2 [Al(OH) 2 ] 6 [S04] 4 or ^A^OM^CSO^

Jarosite............................K2 [Fe(OH) 2 ] 6 [S04 ]t or K2Fe6 [OH] 12 [S04] 4

Natrojarosite .......................Na2 [Fe(OH) 2 ] 6 [S04 ] 4 or Na^FeoCOHJu^SOJ,

Plumbojarosite.....................Pb[Fe(OFI) 2 ]fl [SO.,l 4 or PbFe(i [OH] 12 [S04] 4
HTLI.EBRAND 

AND PENFIELD ] ADDITIONS TO THE ALUNITE-JAROSITE GROUP. 39

In the case of the lead compound one atom of lead, and in the others 

two atoms of either potassium or ,sodiurn, are combined in complex 

molecules containing fifty other atoms; hence that the complex of 

fifty atoms, to the right of the K2 , Naa and Pb in the foregoing formulas, should control or dominate crystallization by virtue of mass effect, 

and condition an isomorphism between such unlike elements as sodium, 

potassium, and lead is not so surprising as would at first appear.

Having adopted the double formulas, as given above, there are 

numerous ways of writing developed formulas, of which the following 

are perhaps the simplest and most satisfactory:

O- S=0 

-O O/ ^O OHO>Fe~°/s \J~pb~(

-0 0. A

)-Fe<QH 

:OH

HO 000 

S O-K K-0 S* 

\ 0 / '

OH

O

It is interesting to note that although K2 , Na2 and Pb play so small 

a r61e in the alunite-jarosite molecules, the substitution of Na2 for Ka 

is attended by a marked variation in the angles of the crystals, 

greater, in fact, than is generally observed in isomorphous replacements. That alunite and jarosite containing potash would be nearly 

alike in their angles is expected, since crystals of corundum and 

hematite are surprisingly alike, as shown by the following comparison:

Hematite, Fe.2 03 .................................

Axial 

length.

1. 3630

. 1. 3656

,. ^ ,./

0 /

93 56

94 00

P / 

57 34

57 37
40 CONTRIBUTIONS TO MINEKALOGY. [BULL. 262.

The relations of the minerals of the alunite-jarosite group are as 

follows:

Jarosite ........................

Plumbojarosite .................

.Axial 

length.

1.252"

1.245 

1.104 

1.216

r ^,,.

0

90 

90 

85 

89

50 

45 

54 

42

c*r

o

55 

55 

51 

54

19$ 

10' 

53 

32

Birefringence.

Positive. 

Negative. 

Do. 

Do.

From the foregoing table it is seen that the substitution of sodium 

for potassium in jarosite has brought about greater variation in the 

angles of the crystals-than the substitution of the bivalent metal lead 

for potassium. . The three minerals, natrojarosite, pliirtfbojarosite, and the Na-Kalunite from'Red Mountain, are very interesting when studied together 

as microscopic mounts, the crystals being practically alike in size and 

development, and illustrating very beautifully on the one hand the 

isomorphism of aluminum and iron, on the other the isomorphism of 

potassium, sodium, and lead. The three substances must have formed 

under like conditions, and it is believed that they are solfatario products, formed under the combined action of heat and pressure. Being 

difficultly soluble, they have formed, like many precipitates, as fine 

crystalline powders.

The three products just mentioned, when heated in closed tubes, 

behave alike; the}7 suffer no change on gentle heating, but Avhen the 

temperature is sufficiently high to decompose the chemical molecules, 

the crystals break up into fine powder or dust, w.hich is carried along 

by the escaping vapors and deposited for a considerable distance along 

the sides of the tubes. In addition to water, SP2 and SO3 are copiously given off during decomposition. In the case of natrojarosite, 

and the same would doubtless hold true for the Na-K-alunite, it is 

found that after ignition one-fourth of the sulphate radicle has been 

retained by the alkali metal, and may be extracted by water. In the 

case of plumbojarosite, however, all of the sulphate radicle is expelled 

by ignition, doubtless because the ferric-oxide present serves to decompose any lead sulphate which might have a tendency to form. Anglesite, PbSO4 , when heated alone in a closed tube suffers no decomposition, but when finely triturated with limonite and heated, acid water 

is given off. Finely powdered natrojarosite and plumbojarosite are 

slowly but completely soluble in boiling Irydrochloric acid. Plumbojarosite when fused with-sodium carbonate on charcoal yields globules 

of lead and a coating of lead oxide.
ADDITIONS TO THE ALUNITE-JAROSITE GROUP. 41

It has seemed to the writers best to designate, the new compounds 

described in this article as natrojarosite andplumbojarosite, the names 

signifying their relation to a well-known species. Other members of 

this group will doubtless be found, and the name " natroaluuite" might 

be employed to designate the two varieties of alunite from Colorado 

mentioned on page 37, where the proportion of the soda to the potash 

molecule is 7 : 4. It is highly probable that a series of alunite-jarosite 

compounds could be made artificially.

It is with pleasure that the writers acknowledge their indebtedness 

to Messrs. Turner .and Porter for calling attention to the interesting 

compounds described in this article.
MINERALS FROM THE CLIFTON-MORENCI DISTRICT, ARIZONA.

By W. LINDGREN and W. F. HILLEBKAND.

In 1902 an examination was made of the Clifton-Morenci copper 

district in Arizona. Study of the collections proved the presence of 

several interesting minerals, a brief account of which is here given. 

The copper deposits at Clifton and Morenci consist partly of irregular 

or tabular bodies of oxidized ores in Paleozoic limestones, partly of 

chalcocite ores connected with fissure veins in a granite-porphyry or 

in the same limestones.

CORONADITE.

On the dump of a small shaft on the west end of the Coronado vein, 

three-fourths of a mile west of Horseshoe shaft, fairly large amounts 

of a dark metallic mineral were found intimately intergrown with 

quartz and decomposing into limonite. The vein at this end shows no 

copper minerals, but is said to contain some gold, and its surface ores 

are reported to have been worked in an arrastre in the early days of 

the camp. In color this mineral is black and its structure is delicately 

fibrous. The hardness is about 4 and the streak black with brownish 

tinge.

A thin section proves it to be opaque, and in reflected light its fibrous 

and homogeneous structure is well brought out. It cements angular 

quartz grains and its secondary nature is clearly indicated. In general aspect it is not unlike psilomelane. A preliminary examination 

showed that it contained the oxides of lead .and manganese. As it did 

not seem to correspond to any known mineral species, an analysis 

was made, after a partial mechanical separation. The results were as 

follows:

Long-continued efforts to procure pure material for analysis by the 

use of heavy solutions were not attended with success. The ultimate 

product of specific gravity, 5.246 at 22°, yielded on decomposition b}^ 

hydrochloric acid a residue of from 6 to 7 per cent, which consisted 

mainly of silica, with a small amount of alumina, etc. Its presence 

would not have mattered much had it been quite indifferent to acids, 

but its partial solubility, as shown by the varying amounts undissolved 

on different trials, and similar varying amounts of alumina and perhaps

42
LHILLERBERNANDD] MINERALS FEOM CLIFTON-MORENCI, ARIZONA. 48

other minor ingredients found in solution, renders the calculation of 

molecular ratios not altogether certain in all cases. The composition 

as found is:

Mn02 ..................................................... « 56.13

'MnO...................................................... 6.56

PbO. ...................................................... 26.48

ZnO....................................................... .10

CuO....................................................... .05

Mo03 ...................................................... .34

Al,08 ....................................................... >>. 63

Fe209 c ---------------------------------------------------- .1.01

H2 0....................................................... ^1.03

Insol. and silica ............................................ 7. 22

CaO, MgO, Alk., and loss................................... :45

TotaK............................................... 100.00

The material available did not permit the quantitative determination of the vanadium, whicti may be present in rather more than a 

mere trace, but neither it nor the phosphorus can influence materially the ratios given below. The vanadium would be effective in 

two ways: (1) by requiring a base for its neutralization, if existing as 

an acid constituent, and (2) by liberating chlorine when acted on by 

hydrochloric acid, and thus affecting the values found for peroxide 

oxygen. If the iron exists in the ferrous state, it too would affect 

the values found for the peroxide oxygen, and consequently for both 

the oxides of manganese. Assuming it to so exist and applying the 

proper corrections, also deducting from the lead oxide an equivalent 

for the molybdenum, assuming its existence as molybdate of lead, the 

following are the results:

MnOs ............................ 56.68+87.0=0.6515 =3.00

MnO ............................ 6.11-*- 71.0='.0861'

PbO............................. 26.96+222.9= .1165

FeO ............................. . 91-4- 72. 0= . 0126 0. 217=1.00

ZnO ............................. . 10+. 81. 0= . 0012

CuO .............................. . 05+ 79. 0= . 0006

H.,0 ............................. 1.03+ 18. 0= . 0572 = . 264

"Mean of 56.10 and 56.16. Total Mn as MnO from MnS04 , 52.38 per cent. Peroxide oxygen, 10.31 

per cent.

i> With a little TiOj., P206 , and V205. 

c State of oxidation not known. 

<t Nothing at 100°, only 0.14 per cent below 200°.
44 CONTEIBUTIONS TO MINERALOGY. [BOLL. 262.

If the mineral is to 'be .regarded as anhydrous, the comparatively 

simple formula K" (Mn,,O7 )" satisfies the above ratio, and it may be 

written structurally .

O=Mn""-O

= Mn""-O

in which R" Pb" or Mn". This is to be regarded as a saturated salt 

of one of the numerous possible derivatives of ortho-manganous acid 

that may be derived from it by removal of water, in the present case 

as follows: ' * 

3H4 Mn04 -5H8 0=H8Mns07

An acid of the same empirical formula would result by removal of 

two molecules of water from three of rnetamanganous acid, H2Mn03 .

It is probably best to rest for the present content with the above 

relatively simple formula and to regard the water found as due to 

incipient alteration. But if the water is to be considered as wholty or 

in part essential, and furthermore constitutional and this may very 

well be the proper view to take then the formula becomes much 

more complex, namely, R4 "H2 (Mn12 029 ), when none of the water is 

allotted to the foreign matter. This formula is still referable graphically to a more highly condensed manganous acid, and a number of 

isomers would be possible.

Such intricate formulas as this should not cause the least surprise, 

however unlikely they may at first appear to be. The great number 

of manganites in varying degrees of saturation and hyd ration observed 

in nature and prepared artificially, some of them of even greater complexity than the above, are certainty not all mixtures of only a few 

simply constituted molecules. A very short study of the graphic 

formula corresponding to the above empirical formula R"4H2 (Mn12 029 ) 

will show what a vast number of closely related bodies are theoretically producible by hydrating the molecule step by step or by adding to 

or reducing the number of bivalent atoms or substituting for them 

those of another valence. Similar varieties in great number would be 

derivable from other condensed manganous acids of both higher and 

lower orders, and it is plain that because of the very slight differences 

in percentage composition between many of them it is almost as hopeless to expect analysis to reveal the exact empirical formula in the 

majority of cases as it is for the enormously complex albuminous
MINERALS FROM CLIFTON-MORENCI, AELZONA. 45

bodies of organic chemistry. This is especially true because in so 

many cases the mineral manganites described are far from being 

homogeneous species. They are either mixtures of -two or more of 

these closely related coniplex molecules or else are contaminated by 

foreign bodies. It is not surprising, then, that so many compounds of 

uncertain formula that may be regarded as salts of manganous acid 

have been prepared in the laboratory or are found in nature. From 

the known tendency of these bodies to form under laboratory conditions which may very well be repeated in their general character in 

nature, it is to be expected that a vast number of mineral manganites 

should exist, and it ought rather to excite surprise than otherwise if 

two or more are not formed simultaneously from the same solution. 

This, together with inherent difficulties of analysis, would offer a 

simple explanation of the fact that so few of the analyses made lead to 

rational formulas. If formed from solution, their original state might 

well be one of hydration either as regards water of crystallization or 

of constitution. The temperature at which the water is expelled in 

the present case indicates constitutional water.

. Our search of the literature has not revealed a native manganite 

carrying a high percentage of lead, although artificial compounds have 

. been prepared. For this reason, and because of its distinctly crystalline character, the present mineral seems worthy of a specific name. 

The one we propose is coronadite, after the famous explorer of that 

portion of the American continent from which the Territories of New 

Mexico and Arizona have been formed.

CHALCOCITE.

The cuprous sulphide (Cu2S) is very common in the Clifton district; 

in fact, it constitutes at present the principal valuable mineral in the 

ores. It occurs chiefly intergrown with pyrite, in the altered porphyry, as disseminated grains or as solid seams or veins which rarely 

exceed 2 or 3 feet in .thickness. It is never crystallized but has ordinarity an earthy or sooty appearance and black color; scratching with 

a knife reveals its semisectile character and metallic luster. In a few 

small massive veinlets the normal metallic luster and dark-gray color 

appear on fractures; a fibrous or columnar structure of the mineral is 

known on small seams in shale from" the Montezuma mine. The 

mineral prefers porphyry, and the great bodies of ore now worked 

"all occur in this rock; but it is not entirety unknown from the irregular deposits in limestone generally carrying cuprite and copper carbonates. A partial analysis of massive chalcocite from the Montezuma 

mine, Morenci, gave 90 per cent Cu2S and 2.4 per cent FeS2 , the latter 

probably mechanical^ admixed.

The chalcocite is everywhere, in this district, a secondary mineral
46 COWTEIBUTIONS TO MINERALOGY. [BULL.262.

formed by the replacement of pyrite by means of descending solutions 

of cupric sulphate. The deposition of the mineral was accompanied 

by the formation of quartz, chalcedony, and kaolin. In the porphyry 

the chalcocite ore along the veins begins 100 to 200 feet below the 

surface and continues to a depth of 400 feet, or even more, when it is 

usually replaced by pyrite, chalcopyrite, and zinc blende.

WILI^EMITE.

This rare silicate of zinc (Zn2SiOJ was found by Mr. Boutwell in the 

form of very small grayish crystals on a fragment of garnet rock in 

the Modoc open cut, on the north side of Modoc Mountain. These 

crystals were identified by Messrs. Pirsson and Penfield, of Yale University, who state that the stout hexagonal prisms look exactly like 

those from the original locality at Mor-esnet.

CALAMINE.

Small transparent orthorhombic crystals of calamine (ZnOH)2 Si03 

were identified on a specimen of decomposed garnet rock from the 

Shannon mine, just above the lime quarry.

DIOPTASE.

The silicate of copper, dioptase (H2CuSi04 ) has been found at only 

a few localities. Very beautiful specimens, which, however, are by 

no means common, have long been known from the 

classic localit}'", the Kirghese Steppes, Russia, and 

more recently from the French Kongo State, Africa. 

Dioptase is seldom found in the United States, the 

only recorded occurrences being at the Bon Ton 

mines, Chase Creek, near Clifton, Ariz., noted by 

R. C. Hills/' and from near Riverside, Final County, 

Ariz., noted by W. B. Smith. 6 Well crystallized 

FIG. s.-Dioptase. specimens of this mineral were found on an old 

dump of the Stevens group of mines, on the west 

side of Chase Creek, near Garfield Gulch. They occurred in a small 

chimney of chrysocolla ore in limestone, now worked out, and the 

locality is.believed to be the same as that described by Mr. Hills. 

The dioptase crystals were submitted to Frof. S. L. Penfield, who 

remarks on them as follows:

The crystals, measuring from 1 to 2 mm. in diameter, occur closely grouped 

together, lining cavities in a brown ferruginous gangue impregnated with amorphous 

green material which is probably chrysocolla. The color of the dioptase is a beautiful emerald-green. The habit of the crystals, shown by the accompanying figure, is 

that which is most commonly observed and is especially characteristic for dioptase; 

prism of the second order a (1120), terminated chiefly by the rhombohedron of the 

first order s (0221) and wich small faces of the rhombohedron of the third order x

a Am. Jour: Sci., ser. 3, vol. 23,1882, p. 325. bProc. Colorado Sci. Soc., vol. 2,1887, p. 159.
I H?I^KRBI KAND!> ] MINERALS FROM CLIFTON-MORENCI, ARIZONA. 47

(1341). As is common on this species, the prismatic faces are vicinal and the s and x 

faces are striated parallel to their mutual intersection edges; hence the crystals are 

not suited for giving accurate measurements of the angles with the reflection goniometer. One crystal was measured, and the angles of one1 of the rhombohedral 

zones, given below, are sufficiently close to the calculated values to establish the

identity of the forms.

Measured. Calculated.

a x, 1120 1341 = 28° 55' 28° 48'

s s', 0221 2021 = 83° 48' 84° 33'

s' a", 2021 TT20 = 48° 18' 47° 43'

By crushing some of the material, embedded in oil under a cover glass, and examination in convergent polarized light, occasional fragments were found which gave 

a normal uniaxial interf<5rence figure, with numerous rings indicating high birefringence. The character of the birefringence was found to be positive. Thus in all of 

its crystallographic and optical relations the material studied is like typical dioptase 

from other localities.

^ CIIKYSOCOLLA.

This mineral (CuSi03 +?iH2O) occurs very commonly in the oxidized 

part of the deposits, but does not, except in some cases, constitute an 

important ore. Oh the whole, it is more abundant in the deposits in 

porphyry and granite than in those contained in limestone. The usual 

bluish green or dirty green colors and conchoidal fracture characterize 

it. It occurs in seams or coatings at many of the mines abundantly in 

the Mammoth mine on contact fissure between porphyry and limestone; 

at several prospects on the Stevens group in Chase Creek near Garfteld Gulch; in the Terazas fissure vein in porphyry, nearMetcalf; at 

the Metcalf mines and many of the prospects between that place and 

Morenci; at the Modoc open cut, Morenci. Technical analyses of 

chrysocolla ore from Terazas mine by the Arizona Copper Company 

gave 

Si02 ........................................................ 31.65

CuO........................................................ 34.90

H2 0...-...-..-.....-....................................... 26.30

A1 2 0S ....................................................... 3.80

Undetermined .............................................. 3.35

100.00

Normal chrysocolla should have 34.2 per cent t3i02 , 45.2 per cent 

CuO, and 20.5 percent H2 0, but the analyses show great divergency, 

many probably being mixtures. Moreover, what has been called 

chrysocolla probabty includes two mineral species.

The optical characteristics of chrysocolla seem imperfectly known. 

Dana states that it is cryptocrystalline, while many other text-books, 

notably one issued in 1902 by Professor Miers, call it "amorphous."

In most cases the mineral indeed seems cryptocrystalline with bluishgray colors of interference, but this is by no means.universal.

Chrysocolla from the Modoc open cut appears as mammillary crusts
48 . CONTRIBUTIONS TO MINERALOGY. [BULL.262.

of bluish-green color on" cqpper-pitch ore." The latter is isotropic 

and undoubtedly a distinct mineral from the chrysocolla, of brown 

color in varying tints, some of it opaque and showing evidence of 

concentric deposition. On top of the chrysocolla are thin crusts of 

quartz and some calcite. The chrysocolla has three different structural forms, as seen under the miscroscope: (1) The dominant mass is 

a cryptocrystalline to microcrystalline aggregate of particles with 

high birefracting index; (2) very fibrous and felted aggregates of 

same substance giving undulatory effects between crossed nicols and 

medium high colors; (3) fibrous crusts on top of l,.or also in thin layers between masses of 1, the individuals having such a remarkably 

parallel orientation that the aggregate of them appears almost like 

single crystals between crossed nicols, with black shadows sweeping 

across them when the table is turned. The extinction is parallel to 

the fibers, double refraction strong, about like augite, character negative. The same optical characteristics were repeatedly observed in 

thin sections of chrysocolla from Metcalf and other places. Reniform 

deposits were sometimes noted, the center of cryptocrystalline material 

coated with coarsely fibrous and highly birefringent material.

Sections from the Coronado and Metcalf mines often showed pseudomorphs of pyrite consisting of a shell of limonite with kernel of fibrous 

chrysocolla.

The observations of Jannettaz" on chrysocolla from Boleo, Baja 

California, Mexico, led to the same results as described above, but 

seem generally to have been overlooked by editors of text-books.

COPPER-PITCH ORB.

Under this old German name is described a dark brown to black 

substance, sometimes dull but generally with glass}7 to resinous luster; 

hardness about 4; streak dark brown. It occurs among the products 

of oxidation of the deposits in limestone, as at the Detroit and Longfellow mines and Modoc open cut at Morenci, and is associated with 

azurite, malachite, and chrysocolla, often inclosing these minerals or 

replacing in branching veinlets, together with azurite, a shale-like 

mass, probably largely composed of kaolin. In thin section it is sometimes opaque, but often also translucent, gradual transitions obtaining 

in the same section, and occurs in irregular or concretionary masses, 

often containing small embedded crystals of a doubtful mineral, possibly a silicate of zinc. Between crossed nicols the translucent mineral 

always proves entirely isotropic and, except for varying depth of color 

and the small crystals mentioned, entirely homogeneous.

"Bull. Soc. Win., Paris, vol. 9, 1880, p. 211.
MINERALS FROM CLIFTON-MORENC1, ARIZONA. 49

A rough preliminary analysis of selected pitch black material from 

the Detroit mine gave

CuO.......................................................... 28.6

ZnO.......................................,.................. 8.4

MnOj ........................................................ 21.2

Fe A+A1A+P A ...I....................................... 4. 0

Insoluble in HC1.............................................. 22. 8

Ignition loss 16.3, less oxygen due to conversion of Mn02 to Mn3 04 . 13. 7 "

98.7

Similar material surmounted by crusts of chrysocolla from the 

Modoc open cut contained much Mn02 , with a good deal of CuO and 

ZnO, and is thus evidently the'same substance. Manganese is largely 

but not certainly wholly present as Mn02 . The insoluble portion 

consists of silica, is wholly separated by acid without need of evaporation, and is nearly all soluble in dilute potassium hydroxide. It is 

not possible to say whether silica is in combination or as opal, but it 

can not be present in any other form.

Most of these copper-pitch ores, known from many districts, have 

been described as impure chrysocolla. As shown by the optical characteristics, they are not, however, a mixture, and they certainly do 

not contain any chrysocolla, the characteristics of which are very 

different. They probably represent a series of closely related compounds, the chemistry of which has not yet been fully elucidated. 

Prof. G. A. Koenig" describes a similar mineral with the same isotropic character from Bisbee, and names it melanochalcite. Its composition is different, since it contains

CuO'. ................................................... T ... 76. 88

SiO., ........................................................ 7. 80

CO, ............:..............-............................. 7.17

H2 0 ...."..................,................................. 7. 71

ZnO ........................................................ .41

FoS, .......................:................................ .07

100. 04

Professor Koenig considers it most probably a basic salt of an orthosilico-carbonic acid. No carbon dioxide was found in the Morenci 

minerals. In conclusion it would seem that the chemistry of these 

copper-pitch ores would bear further examination.

MORENCITE.

In a lime shale on the intermediate level of the Arizona Central 

mine, Morenci, 200 feet below the surface, brownish or greenish 

spreading mases were found, containing brownish yellow, silky fi.brous 

seams. The inclosing material consists largety of the same material

«Am. Jour. Sci., ser. 4, vol. 14, Dec., 1902, p. 404. 

Bull. 262 05- 4
50 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

as the seams, but impure and mixed with a little chlorite and pyrite. 

The whole bears evidence of being a product of oxidation of some 

contact metamorphic mineral.

The fibrous mineral on the seams forms a felted aggregate as seen 

under the microscope, but it is well individualized and contains few 

impurities except a little pyrite and chlorite. The minute fibers are 

brownish yellow and slightly pleochroic, being darker when parallel 

to the principal section (opposite the behavior of biotite); the birefringence is strong and extinction strictly parallel to the fibers. No 

mineral corresponding to this has been described, but, although its 

individual character is beyond doubt, the analysis does not lead to a 

satisfactory formula. The material for the analysis was picked out 

carefully under the lens and examined under the microscope it proved 

satisfactority pure.

The analysis afforded the results of the first column of figures below. 

In deducing the molecular ratios of the second column there has been 

deducted sufficient lime to form apatite with the phosphoric oxide.

Molecular ratios. 

Si02 ............................... 45.74 757 =10. 71 or 11

Ti02 .--..--.---................... trace

A1 2 03 ------------------------------ 1-98 019-. '

^205 = 2. 90 or 3 

Fe2 03 ----------------------------- 29.68 186/

FeO............................... .83 011-j

MnO..........:................... trace

CaO............................... 1.61 027

141 = 2. 00 or 2 

MgO .............................. 3.99 100

K2 0............................... .20 002

Na2 0..--.....-........-.-.-....... .10 001

H2 0 105° .......................... 8.84 491 = 6.96 or 7

H2 0150°.......................... .12

H2O below redness................. 4.27 282 = 3.99 or 4

H20 redness ....................... .69

CuO....... ......................... little

FeS2 .............................. .66

PA .............................. .18

98.89

It would seem from the temperatures at which the water is driven 

oft' that this must exist in two conditions, and that four-elevenths of 

it must be held more securely than the remaining seven-elevenths. 

The attempt to account for four molecules of water as constitutional, 

however, led to no simple or seemingly probable formula, whereas if 

all water is excluded the ratio is that of a metasilicate R"2R'"5 

(SiO3 )"n . On the other hand, to include the whole of the water as 

essential tp the silicate molecule^ for which there is little ground in
LTNDGKEN AND"] 

' HILLEBKAND. J MINERALS FKOM CLIFTON-MORENCI, ARIZONA. 51

view of the ease with which most of it is expelled, leads to an orthosilicate ratio R'M R"aR'"6 (Si04 )""u .

On the whole, considering also the bad summation of the analysis, 

it is more rational to regard the mineral as a hydration product of an 

original metasilicate molecule than to attempt to construct a complex 

formula which could have but a veiy doubtful value. As the mineral 

is not a mixture, but "is optically well individualized, we have, after 

some hesitation, thought best to designate it by the name morencite, 

derived from the locality in which it was found.

HBETHENITE.

This hydrous, basic phosphate of copper (H2Cu4P2 010) was found 30 

feet below the adit level of the Coronado lode, in the main shoot. It 

is a matter of interest to record its occurrence, for this rare mineral 

has never before been noted in the United States. It occurs in small 

crystals, less than 1 mm. in length, deposited in cavities and seams-in 

a quartzite gangue. The mineral was identified by 

Prof. S. L. Penh'eld, who"also kindly measured and 

figured the crystals. Professor Penh'eld describes 

the occurrence as follows:

The only associated minerals are occasional clusters of minute quartz crystals and small tufts of radiated malachite 

needles. The color of the libethenite varies from light to 

dark olive-green, depending upon the size of the crystals. 

The habit of the crystals, as shown by the accompanying 

illustration, is a combination of the prism m (110) and brachydome e (Oil)! which is exactly like that commonly observed 

on libethenite from foreign localities. On an occasional crystal

the brachypinacoid b (010) was also observed. Although the crystals are brilliant, 

the faces are generally vicinal and give uncertain or multiple reflections of the 

goniometer signal. The best reflections were obtained from the faces of the dome e, 

and three measurements of e e/, Oil Oil gave 69° 52', 70° 18', and 70° 14'. The 

last measurement, obtained from the best reflections, is close to the value, 70° 8', 

obtained by Eose. The best measurements of the prismatic angle gave m <* in"', 

110 ^ 110 = 87° 11/, which, considering the vicinal character of the prismatic faces, 

is reasonably close to the value of Rose, 87° 40', as given in Dana's Mineralogy. 

A small crystal resting on a prismatic face, when examined in convergent polarized 

light, showed an optical axis nearly in the center of the field, with the dark bar 

running at right angles to the vertical axis, thus indicating that the optical axes are 

in the plane of the base, as determined by Des Cloizeaux. The presence of copper, 

water, and phosphoric anhydride was determined by chemical tests.

A more detailed search would probably reveal small quantities of 

phosphates from other mines near Morenci. They are certainly hot 

abundant.

FIG. 4. Libethenite.
52 CONTRIBUTIONS TO MINERALOGY. [BOLL.262.

BROCIIANTITE.

This basic sulphate of copper (H6Cu4S010 ) is usually supposed to be 

one of the rarer minerals. It was, however, discovered at a few places 

near Metcalf and Morenci, in well-developed crystals, and this led to 

a systematic microscopic examination of the green ores, hitherto supposed to be malachite. The result was surprising, as the mineral was 

proved to be of extremely common occurrence, mostly intergrown 

with malachite, which had effectively masked its presence. It is 

believed that a careful examination of many so-called malachites from 

other districts will disclose the overlooked importance of brochantite 

as a copper ore.

Brochantite is frequently crystallized in the short but stout rhombic 

prisms combined with dome and brachypinacoid characteristic of the 

species. Needle-shaped and flat crystals are more rare. The crystals 

are usually of small size and frequently microscopic-. It occurs as 

lighter or darker emerald-green crusts on limonite or sericitized porph}Ty from the red ore body in the Shannon mine, from the Metcalf 

mines and many other places; as fine-grained aggregates in altered 

porphyr}^ at the Shannon mine, near the surface, constituting valuable ore with as much as 30 per cent copper; from croppings of the 

King vein, filling seams and coating porphyry fragments as flat pieces 

or .even foils with almost pearly luster; from the croppings of the 

Copper Queen mine between Morenci and Metcalf. here as flat stellar 

aggregates of bluish green foils; at many places near Morenci, as, for 

instance, Copper Mountain and Montezuma mines, at the latter locality 

replacing chalcocite. It would probably not be found absent from 

any mine, in the district containing oxidized copper ores. Malachite 

often develops later than the brochantite.

On the whole, the mineral is most abundant in fissure veins in porphyry, though also occurring in the irregular deposits in limestone.

Brochantite has an excellent cleavage parallel to the brachypinacoid. 

The macropinacoid is the axial plane and the acute bisectrix is seen 

emerging in cleavage foils. Pleochroism. very slight. Birefringence 

much lower than malachite, about equal to that of augite. This, as 

well as the absence of twins, distinguishes brochantite from malachite. 

The reaction for sulphuric acid is of course a valuable aid.

SPANGOLITE.

This peculiar mineral (H18Cu6AlClSO19 ), essentially a highly basic 

chloro-sulphate of copper and aluminum, was discovered and described 

by Prof. S. L. Penlicld a about fifteen years ago. The specimen came 

from some point within 200 miles of Tombstone, Ariz., and probably

a Am. Jour. Sci., ser, 3, 1890, vol, 39, pp. 370-378,
MINERALS FROM CLIFTON-MORENCI, ARIZONA. 53

from one of the great copper camps of the Territory. Somewhat later 

it was identified by Prof. H. A. Miers on two specimens from Cornwall, England, but the American locality has not yet been found. It 

is, therefore, a matter of interest to record its discovery on some specimens from the Metcalf mine of the Arizona Copper Company, taken 

from the workings in the great open cut not more than 100 feet below 

the surface. These specimens consist of white sericitized graniteporphyry, in part silicified, and traversed by veinlets and irregular 

masses of cuprite; the cuprite contains native copper and is covered 

by crusts of malachite, brochantite, and chrysocolla. A soft and scaly 

bluish-green coating on the chrysocolla proved to consist of microscopical hexagonal crystals or cleavage foils, remaining dark between crossed 

nicols. The mineral was identified as spangolite, a determination in 

which Professor Penfield concurred. No measurable crystals were 

found, and the mineral is very inconspicuous. It is difficult, if not

impossible, to obtain material entirely free from other minerals.

Selected bluish flakes from this specimen gave tests for water, and 

the sulphate and chlorine ions, besides copper. There was too little 

of this pure material to permit of a test for alumina, but the mixed 

copper minerals composing the greater part of the specimen showed 

the presence of this body. It seems therefore probable on these 

grounds alone that the bluish flakes are spangolite. Vanadium, phosphorus, and arsenic are absent.

The closed-tube reactions of the mixed copper minerals are veiy 

'striking. Water is given off first. Then appears suddenly a white 

sublimate (A1C13 ?) near the assaj^, which seems to form or at once 

change to minute colorless drops. This .deposit can be driven slowly 

up the tube, followed at its lower, sharply defined edge by dark yellowbrown drops (CuCL,?), which on cooling solidif^ to greenish crystalline aggregates, and the part of the tube between them and the assay 

shows under the lense delicate feathery crystallizations like frost markings on window panes. Down in the flame the glass becomes colored 

red (Cu2O?) and in parts yellow. On charcoal the blowpipe flame is 

colored azure blue and at the same time green.

In order to compare the above closed-tube behavior with that of 

undoubted spangolite, a small fragment of the latter, offered by Professor Penfield, was tested. It gave water and then a white sublimate 

like the one above mentioned, followed by a dark olive-brown liquid, 

which on cooling passed through lighter shades of color and solidified 

as a bright-green ring. In general this behavior is very like that of 

the mixture under examination from Clifton.

GERITARDTITE.

. The cliffs" of granite-porphyry in the deeply eroded Chase Creek 

Canyon at Metcalf in many places show a conspicuous and extensive 

bright green coating of some copper mineral, which, no doubt, is
54 CONTRIBUTIONS TO MINERALOGY. [BULL.202.

formed by the trickling of atmospheric waters over and through rocks 

containing a small percentage of copper. This is not surprising, for 

porphyry in this vicinity is altered throughout by quartz cementation 

and disseminated cupriferous pyrite. This'"green paint," as it is 

frequently called, is not soluble in water, and more closely examined 

consists of small dark-green, roughly mammillary forms, coating the 

rock to a thickness of a few. millimeters. Examination by the microscope fails to reveal any recognizable mineral in the "cry ptocrystal line 

mass.

Chemical examination led to the interesting result that the copper 

minerals present consist of a nitrate and a chloride, neither of which 

has been found elsewhere in the mines of the district. Detrital grains 

and some silica seem associated with these compounds. The nitrogen 

seems difficult to account for in the absence or scarcity of animal substances which might have yielded it.' Possibly it is contained in the 

porphyry.

The closed-tube reactions of the copper minerals forming the 

mixture on this specimen are as striking in. their way as those of 

the mixture containing spangolite, described elsewhere. Water'first 

appears, then brownish nitrous vapors, followed by a sublimate which 

is not very volatile, becomes black on further heating but on cooling 

yellow-brown. The glass at the bottom of the tube is often yellowbrown when cold. After some hours the sublimate nearly disappears 

or becomes greenish from absorption of water. If the water which 

condenses in the upper part of the tube on first applying heat is driven 

out by the flame,' and the mouth of the tube is held in the flame, this 

is colored deep green by a volatile copper compound (chloride?). On 

charcoal the flame is azure blue and at the same time green. Vanadium is absent.

The mixture contains presumably the basic nitrate gerhardtite 

(H6Cu4N2O12 ) and a chloride which is perhaps atacamite. Spangolite, 

the chloride, can hardly be present, for the slight .amount of SOS shown 

by test does not seem sufficient to account for the large amount of 

chloride.

The only place from which gerhardtite has previous^ been identified 

is at Jerome mines in the central part of Arizona, associated with 

cuprite and malachite. It was discovered there by Messrs. H. L. Wells 

and S. L. Penfield.
TWO TELLURIUM MINERALS FROM COLORADO.

By W. F. HlLLEBRAND.

1. EMMONSITE (?) FROM A NEW [LOCALITY.

Messrs. F. L. Ransome and Waldemar Lindgren, of the Geological 

Survey, collected, in the W. P. H. mine at Cripple Creek, a green mineral which has been observed in other mines there, and which on examination in the laboratory showed close resemblance to the emmonsite 

described by the writer nearly twenty years ago." It differed from 

it, however, in outward appearance by assuming marnmillary forms 

instead of crystalline plates. In its optical properties, so far as they 

were determinable, there is perhaps no positive disagreement with 

those reported for emmonsite. Mr. W. T. Schaller reports as follows:

There are two cleavages, one paralled to 6(010) and another parallel to a form in 

the orthozone. Axial plane parallel to 6(010). Bxa perpendicular to a cleavage face 

in the orthozone. The extinction on the clinopinacoid is inclined 25° to 30° to the 

vertical axis. 2E is approximately 40°. Double refraction medium, and the mineral nonpleochroic.

The gangue in which the specimens were found is granite and schist, 

close to their contact with a porphyritic breccia, in a vein pocket, at a 

distance of about 150 feet froui the surface. Associated with it was 

very rich native gold ore and also tellurite, though neither of these 

was apparent on the few specimens that came to the laboratory. . .

Like emmonsite, the mineral melts at a low heat to a red-brown liquid, 

but, unlike it, gives on stronger heating only tellurous oxide with no, 

trace of selenium or selenious oxide. Analysis confirmed the absence 

of selenium. Its density, too, differs from that of emmonsite, if the 

determinations in both cases on scant}r material are to be depended 

on. After allowing for gangue, the original emmonsite was judged to 

have a density of at least 5, while that of the present mineral is but 

little above 4.53, after allowing for 24.44 per cent of gangue, consisting mainly of quartz, and to which the specific gravity of quartz was 

assigned. .

In its appearance the present mineral would seem to resemble 

durdenite more than emmonsite, but the marked difference in water

a Proc. Colorado Sci. Soc., vol. 2, p. 20,1885.

55
56 CONTRIBUTIONS TO MINEEALOGY. [BULL. 202.

content differentiates it sharply from that mineral, durdenite yielding 

over 10 per cent.

After deducting 22.44 per cent of gangue containing over 90 per 

cent of silica, three portions of from 0.15 to 0.20 gram net weight 

each gave the following results:

Te02 .......................

Fe2 0v --------------- ------

H2 0at 100°................

H20 above 100° ............

p n

A120,----------------------

Si02 , etc.« .................

i.

70.83

22.67

| 4. 68

2.

71.80

22.81

4.82

.34

.58

3.

70.20

22.79

{ "

.54'

Mean.

70. 71

22.76

.21

4.54

.34

.56

.88

100. 00

Ratios.

3.16

1.00

1.77

«Includes alkalies, traces of magnesia and gold, and a small amount of a metal or metals precipitable by hydrogen sulphide whose identity co.uld not be established.

Allowing the alumina' to offset the P2O5 , though it may belong to 

a soluble silicate or to the tellurite, and a small portion of iron be 

demanded for the P2O6 , the ratios given in the final column result. 

They are as unsatisfactory as those afforded by the original emmonsite, which were for Fe2O3 to Te02 , 1:3.65 in the original description 

and 1:3.75:1.82 for Fe2 03 : Te02 : H2 0 if the supplementary determinations in Am. Jour. Sci., vol. 40, p. 81,1899, are accepted. The presence of tellurite in association with the green mineral suggests a possible 

explanation of the failure to obtain a simple ratio, though such contamination was not noted in the material analyzed nor on the neighboring gangue. If this explanation is correct, however, the variation 

from the original emmonsite ratio becomes still more marked. Provisionally, the mineral may be regarded as emmonsite.

The above results are given in some detail, notwithstanding their 

inconclusiveness, because of the importance of accumulating data 

regarding the as yet small but interesting group of ferric tellurites, 

and inciting collectors and mining men to careful search for and preservation of further material for more extended study.

Thus far emmonsite, durdenite, and an unnamed mineral from 

Cripple Creek, described by Knight in Proc. Colorado Sci. Soc., 

vol. 5, p. 66, and affording likewise unsatisfactory ratios, comprise 

the list of natural ferric tellurites, the formula of no one of which can 

be regarded as established be}?ond question.
HILLEBRAND.1 TELLUEIUM MINERALS FEOM COLORADO. 57

a. TETRADYMITB.

Specimens received in the Survey laboratory from Mr. H. B. Trader 

and said to come from some locality near Whitehorn, Fremont County, 

proved to be tetradymite. They showed the mineral in masses of 

considerable size, which, although manifesting the eminent cleavage 

of tetradymite, were devoid of distinct evidences of crystal form. 

The specific gravity at 20° C. was 7.816. Analysis afforded the following results:

Bi....... ..........

Te ................

Se. .................

s...... ...........

Fe2 0:! --------------

Insoluble .-..-.....

I. 

52.00

46.62

«. 20

.13

.22

.15

2.

52. 30

j 46. 82

'.14

 3.

52. 13

Mean.

52.14

( 46. 62

1 .20

.14

.22

.15

99. 47

Atomic ratio.

0.2498 =2.0

.3651]

.00251=2.98

.0044J

"Approximate.
NOTES ON LAWSONITE.

By W. T. SCHALLER and W. F. HILLEBRAND.

Crystals of lawsonite are very simple in their combinations, the 

common forms being the prism, base, and brachydome. Two habits 

occur tabular crystals with {OOl} and {110} and ci^stals with the 

.forms {110} and {Oil}. The brachypinacoid and the brachydome {041} 

also occur; A large number of crystals from the t}7 pical locality in 

Marin County, Cal., were collected by the writer and carefully examined with a hand lens for any additional forms. Only two new forms 

were determined.

The forms observed on the six crystals measured are:

^=01=011

r= 2=221 

s= 3=331

c=0 = 

&=0oo=010

77?,= 00 =110

The angles measured, with those calculated for these forms, are 

quoted in the table following:

No. '

1

2

3

4

5

6

7

Letter.

C .

b

m

d

e

r

s

Symbol.

Gelt.

0

Oco

oo

01

04

2

3

Miller.

001

010

110

Oil

041

221

331

Measured.

</>.

O r

0 00

56 ' 22

0 09

0 00

56 27

56 22

pO I

0 02

90 00

90 00

36 36

71 18

69 10

76 21

Calculated.

* 

0 I

0 00'

56 22

0 00

0 00

56 22

56 22

po i 

0 00

90 00

90 00

36 27

71 18

69 27

75 58

58
SCHAU.EK AND~j 

HILLEBKAND. J

NOTES ON LAWSONITE. 59

The new pyramid r=2={22l} is present on two crystals, the faces 

giving good reflections. Fig. 1 shows one crystal on which this form 

occurs.

The new pyramid s=3={33l} is present on only one crystal and 

but one face of the form occurs. The relative size of the face is 

about the same as that of the preceding pyramid. The reflection was 

fair.

The brachydomes are usually deeply striated, rendering it difficult 

to determine with certainty any domes present. On two crystals 

reflections were obtained from two faces, measurements of which 

agree with the angles calculated for the form {034}. The form is 

rather uncertain and is not included with the others.

Measured. 

</> P

0° 23' 28° 07' 14' 

0° 00' 28° 07'

Calculated.

0° 00' 28° 59'

The combinations observed on the crystals measured are shown in 

the following table:

Cryst. No.

1

2

3

4

 5

6

. .

b

. .

c b

b

c

m

m

m

m

in

m

, d

d

d

d e

d

d e

r

..' S

r

. . . .

--

FIG. 5. Lawsonite.

The following table is a calculation of the two new forms corresponding to the tables given in Goldschmidt's Winkeltabellen.

No.

. 6

7

Letter.

? 

,sSymbol.

2

y

Miller.

221

331

0.

o /

56 22

56 22

po /

69 27

75 58

too /

65 45

73 17

i?oo /

55 54

65 42

*.

o /

51 13

53 53

iO 1

31 14

32 30

X

(Prism) 

(x:y).

2.2204

3.3306

V1.4770

2.2155

d= 

t<j p.

2.6667

4.0001'
60 CONTE1BUTIONS TO MINEEALOGY. [BULL. 262.

Material carefully purified by the Thoulet solution followed by 

repeated electromagnetic extraction, and having then a specific gravity 

of 3.121 at 25°, gave the following results on analysis: a

Si08 . .....................................

TiO....... ................................

Al,0,---- ----...---.-----.-.-.--.-.-..--.

Fe2 03 . . ...................................

FeO.... ..................................

MnO....... ..............................

CaO.... ..................................

MgO ....... ...........................

KS0. .....................................

Na2 0..................... ................

H2 0 (ignition) ...................... ......

Total...............................

38.45

.38

31.35

.86

.10

faint .tr.

17.52

.17

.23

.06

11.21

100. 33

Molecular 

ratio.

1.98

I .97

1.00

1.95

Calculated for 

the form ula 

HjCaAloSioOnj.

38. 34

32.44

17.80

11.42

100. 00

Titanium is not considered in the ratio because probably present as 

an inclusion of rutile or titanite. If the latter, the ratio would perhaps approximate still more closely to the theoretical than it does. 

The agreement with the formula deduced by Ransome and Palache 

from their rather widety differing analyses is very satisfactorj^. The 

behavior of the mineral before the blowpipe is somewhat different 

from that given by those authors, or rather their statement needs 

amplification. On first applying the flame a splinter appears to fuse 

easily, as stated, and there is formed a blebby glass, or on larger 

splinters a porous sinter, but this fusing is only momentary, and it 

requires the highest heat attainable, under which the fragment emits 

quite an intense light, to produce a further spftening and rounding of 

the edges. If a rather large splinter is held in the flame of the blowpipe, or in a small flame of a blast lamp, a very sudden and marked 

exfoliation is observed, but even the extruded points and edges do not 

fuse completely in the highest attainable heat. The semifused surface, 

however, appears dark on cooling, sometimes nearly black where the 

heat was most intense. In producing this exfoliation, if care is taken 

to apply the flame but for a moment, it has been noticed that a singularly shaped excrescence may shoot out from a point of the surface.

"Concerning this purified material, Doctor Ransome reports as follows:

"I should say the material is as pure as it is possible to get it. The grains arc all lawsonite, but 

vary in individual purity. Some are perfectly clear. Others have minute inclusions, which appear 

in most cases to be solid particles but are too minute for identification. One of them, however, was 

suggestive of rutile. Some of the grains are slightly clouded with a yellowish stain which the microscope is unable to resolve into distinct particles. There are apparently a few fluid inclusions also."
THE COMPOSITION OF YTTRIALITE. WITH A CRITICISM OF THE 

FORMULA ASSIGNED TO THALtfNITE.

By W. F. HlLLEBKAND.

In a paper describing the new yttrium silicate thalenite/' the author, 

C. Benedicks, casts doubt o'n the formula assigned by Hidden and 

Mackintosh 6 to their mineral yttrialite from Llano County, Tex., for 

which they deduced the formula R2 03 2Si02 or R2 Si 2 07 , in which R2O3 

includes the sesquioxide equivalents of very considerable percentages 

of monoxides and dioxides. Benedicks would assign yttrialite to a 

group of which rowlandite is the prototype and to which he believes 

thalenite and kainosite belong, these being either plain basic salts of 

H6Si 2O7 of the type JK."K/" 4Si4O1B or derivatives in which the fifteenth 

oxygen atom is replaced by its equivalent in fluorine (rowlandite) or 

C03 (kainosite), as shown below.

H2 < >O Thalenite. 

Y = Si2 07 =Y/

Y = Si2 07 =Y,

Fe< >O Yttrialite.

Fe< Rowlandite. 

Y = S1 2O7 = Y-F1

Ca = Si 2 07 =Yx

H4< >CO3 Kainosite. 

Ca=Sl2 07 =Y/

Benedicks says:

Bern Ytt'rialit, von Hidden and Mackintosh beschrieben, sollte die Formel R2 03 , 

2Si02 zukoinmen, \voriii R hauptsiichlich Ytter- und Thorerde 1st. Dabei \vird aber 

ca. 4fo Eisenoxydul in der Analyse vernachliissigt. Wird dies nebst etwas Kalk und 

Bleioxyd mitgerechnet, so bekomint man die Formel Fex/0, 2R2 0;i , 4Si02 , analog 

mit der des Thalenits, welche besser die Zusammensetzung des Yttrialits wiedergibt, 

obgleich die Ubereinstimmung gar nicht gut ist.

a Bull. Geol. lust. Upsala, 4, 1898, 1. b Am. Jour. Sci., ser. 3, vol. 38, 1889, p. 477.

61
62 CONTRIBUTIONS TO MINERALOGY. x [BULL.262.

It is, however, not true that Hidden and Mackintosh neglected to 

take account of the ferrous iron, etc., of their analysis. It was 

regarded in the derivation of their empirical formula R2 Si2O7 . How 

wholly unwarranted was the substitution by Benedicks of his formula 

for yttrialite is shown by the molecular ratio for RO: R2 03 : Si02 , which 

he gives as 1:2:4 instead of 1:3.25:7.42, as calculated by me from 

Mackintosh's figures, wherein for a sound reason I have converted his 

U03 into UO2 , thus throwing it with the ThO2 , where it naturally 

belongs. The agreement is indeed "gar nicht gut."

Benedicks has made the graye mistake of counting Mackintosh's 

monoxide bases a second time, thus making a basic salt R"R'"t Si4 015 

instead of the normal one R"'4 Si4Ou, to which Mackintosh's results 

closely conform.

DISCUSSION OF BENEDICKS'S FORMULA FOR THALENITE.

Moreover, in the light of the data furnished by Benedicks himself 

it can not be admitted that the formula H2Y4Si4O15 for thalenite is 

established.

Water was determined by him according to Penfield's method," but 

without any hint as to the particular modification employed. If, as 

seems probable, the water expelled from the mineral was caused to 

recondense in the cooler part of the ignition tube, the latter beingthen weighed, and again after driving the condensed water out, two 

serious sources of error have to be considered: (1) The CO2 present in 

the mineral, which would count in part as water unless a very careful 

correction was made, as provided for by Penfield. No mention is 

made by Benedicks of any such correction. (2) Nitrogen and helium 

are said to comprise 1.4 per cent of the mineral by weight. If so, 

these would introduce an error in the above water determination of 

contrary sign to that due to C02 , and if the proportion of helium were 

large this error might be of very considerable magnitude.

In an appendix to his paper Benedicks gives an analysis of what he 

considers to be a very pure form of thalenite. He makes no comparison of this with his earlier analysis, nor does he deduce a molecular 

ratio, which I find to be 1:2.6:5.15, or 1:3.03:6.02 if small amounts 

of lime, magnesia, and soda are neglected, instead of .1:2:4, as required 

by his formula. There being no CO2 in this purer material, the value 

for water (if determined as above surmised) may be supposed to bo 

affected only by the error due to nitrogen and helium. It will be 

seen that the neglect to regard lime, magnesia, and soda in his second 

analysis affects the ratio very serious!}7 . .This neglect may be justified 

in figuring on his first anatysis because of an approximate balancing 

by CO2 , but it would be by no means so in the other, in spite of the 

very satisfactory ratio obtained and leading to the empirical formula

a Am. Jour. Sei., ser. 3, vol. 48,1894, p. 31.
HILLEBRAND.] COMPOSITION OF YTTEIALITE. 63

R"R'"6 Si6 0a2 , which is susceptible of a variety of interpretations. It 

may represent a basic salt of diorthosilicic acid E/'R'"5 (R'"0)'(Si 2 07 ).t 

or of metasilicic acid R"R"'2 (R'"0)'4 (Si03 )6 , or possibly even of other 

acids.

Finally, if the values for nitrogen and helium are really anywhere 

near so great as given, an additional argument against the validity of 

his formula is furnished. For in the light of Kohlschiitter's recent 

researches "and my own less conclusive work of a much earlier date,& 

it is in the highest degree probable that nitrogen and helium are not 

occluded in uraninite and other minerals, but are in chemical combination. Now, if this is so, in a mineral containing as much as 1.4 per 

cent of nitrogen by weight, this .must, quite irrespective of its form of 

combination, play so important a r61e in the molecule as to utterly 

invalidate any formula based on calculations from which it is omitted. 

If the above percentage is made up in large part of helium, its effect, 

because of its low atomic weight, must be vastly greater than that of

nitrogen.

Until light is thrown on the nature of the combinations these two 

gases form in minerals, no very positive conclusions can be reached as 

 to the formulas to be assigned to those minerals which contain them in 

more than traces.

CHEMICAL INVESTIGATION OF YTTKIATjITE.

At the earnest request of Mr. W. E. Hidden, the discoverer of 

yttrialite, I undertook to reanalyze the mineral in order if possible to 

.settle definitely the question of its composition. This seemed especially desirable since a large quantity of very fine material was 

available. .

The appearance and behavior of the mineral agreed in all respects 

except one with those of the original description/ It is there stated 

that the strongly ignited mineral is insoluble in acid. This is a mistake, for when powdered its solubility in hydrochloric acid is even 

then perfect, although not rapid.

Careful examination of thin sections under the microscope showed a 

condition that augured ill for decisive analytical results despite the 

apparently fine quality of the large specimens. Distinctly foreign 

mineral fragments were as good as absent except for insignificant 

coatings of a white alteration product, presumably a carbonate, but 

considerable shading was apparent in the slides, indicative of alteration or intimate contamination in the mass of the mineral itself. 

However, after treatment with hot dilute hydrochloric acid (whereby 

much yttrialite was dissolved) followed by dilute sodium carbonate, the

a Ann. cter Chem., 317,1901, p. 158.

& Bull. U. S. Geol.-Survey No. 78,1891, pp. 70-78.

o Am. Jour, Sei v ser, 3, vpl. 38,188,9, p, 477.
64 CONTRIBUTIONS TO MINERALOGY. [BULL.-252.

clear glassy residue appeared to be improved in appearance and the 

specific gravity of two samples, each composed of small grains uniform 

in size for each sample, had risen from 4.596 and 4.590 to 4.654 at 

23i°C. and 4.646 at 26° C., respectively. The two sizes were then 

mixed, giving one sample of about 4.65 sp. gr. at 25° C. That of the 

unpurified material analyzed by Mackintosh was 4.575.

Qualitative tests showed the absence of zirconium, glucinum, and 

aluminum and the presence of a little more than a trace of fluorine, of 

a very little carbon dioxide, besides some other gases which were set 

free by treatment with acids and b}^ fusion with an alkali carbonate.

Silica was separated by two evaporations with hydrochloric acid; 

lead was then thrown out by hydrogen sulphide.

The earths when finally collected together free from all iron, manganese, uranium, titanium, phosphorus, calcium, and magnesium, 

were ignited and weighad. No filtrate from a precipitate of earth 

oxalates was ever regarded as free from earths till after evaporating, 

igniting, and retesting. This is a needed precaution in all similar 

analyses.

The combined earths were dissolved in nitric acid and evaporated to 

dry ness. A, saturated solution of potassium sulphate was poured upon 

the dry mass, which wholly dissolved but almost at once began to deposit double sulphates. Solid potassium sulphate was then added in 

crystals. After twenty-four hours the precipitate was collected on a 

filter and washed with the precipitant solution. Twice was this precipitation repeated after first dissolving the double salts in acid, precipitating by potassium hydroxide, washing, redissolving in nitric 

acid, and evaporating. Then only was the extraction of the yttriumerbium group practically complete. From the combined filtrates the 

soluble earths were thrown out, reconverted into nitrates, and again 

treated with* potassium sulphate, whereby a little further insoluble 

matter was obtained. Yttrium-erbium oxides obtained from the oxalates gave a light-colored mixture of 265.6 Mol. W. (103.8 At. W.), 

which furnished a pink nitrate solution showing the erbium absorption bands strongly marked, with very faint indications of the strongest band of the didymium components.

The insoluble sulphates were converted into chlorides and thrice 

treated with potassium hydroxide and chlorine to precipitate thorium 

and cerium. From the filtrates the soluble earths were recovered and 

subjected to a repetition of this treatment. Their oxides after purification were light dirty brown when heated over the Bunsen flame, but 

grayish white when blasted. Their Mol. W. was 335.5 (At. W. 143.7); 

their nitrate solution was pink and gave the characteristic didymium 

component absorption bands altogether free from those of the erbium, 

constituents.
HIU.EBRAND.] COMPOSITION OF YTTEIALITE. 65

Cerium and thorium were separated by a combination of the ammonium oxalate and thiosulphate methods. The weighed thoria was 

pure white, the ceria of a pale salmon color.

The condition of the uranium was shown by its precipitability as 

tetraffuoride on dissolving the mineral in hydrofluoric acid. This 

reaction afforded a ready means of estimating with exactness the 

ferrous iron by permanganate after rapidly filtering off the fluorides 

precipitated in an atmosphere of carbon dioxide. Solution of-the 

mineral in a sealed tube with dilute sulphuric acid allowed of finding 

the oxygen1 value of both U02 and FeO by permanganate. The result 

thus found for UO2 agreed rnarvelously well with that calculated from 

the U3 0g found gravimetrically in a separate portion.

SiOj .................................

TiO,. ................................

ThO, ................................

UO, .................................

Ce2 0,---- ............................

La-jO,), etc ............................

YAi etc. ............................

a

a

. u

AI./V-- ------ .......................

FeA-- ...............................

FeO .................................

MnO ................................

PbO. ................................

CaO .................................

MgO. .................... ............

HjO above 105° C. ....................

H20 below 105° C .'.........-........:.

CO,.... .................... ^.......

l\05 . ................................

N.He...i 

ri,A,k ..} diff --------

Hillebrand.

29. 63 

.05 

10.85 

«1.64 

3.07 

C5.18 

«43. 45

.76 

1.96 

.88 

.80 

.67 

.16 

.32 

.04 

.11 

.12

.31

100. 00

Molecular 

ratios.

0. 4938

| . 0470 

 . 1930

 . 0608

Mackintosh.

29.17

12.00 

&.79 

1.86 

<*2. 94 

/22. 67 

f/5. 30 

A4. 50. 

'14. 03 

.55

2/89 

.77 

.85 

.60

} .79

99.75

Molecular 

ratios.

0. 4861

| .0483 

. 1864

. 0655

(i Volumetrically. Gravimetrically 1.62 per cent. 

f>Given as .83U03 bv Mackintosh, 

c At. W. 143.8 (Mol.'\V. 335.6). 

f'At. W. 162(Mol. W. 372). 

«At. W. 108.8 (Mol. W. 265.6).

Bull. 262 05 5

/At, W. 110.3 (Mol. W. 268.6). 

(/At. W. 110.53 (Mol. W. 269.06). 

/iAt. W. 114.9 (Mol. W. 277.8): 

iAt. .W. 120 (Mol. W. 288).
66 CONTKIBUTIONS TO MINEEALOGY. [BULL. 262.

Nitrogen (?) and helium (?) were obtained quantitatively by fusing 

the mineral with sodium-potassium carbonate in a current of carbpn 

dioxide and collecting the gases in a nitrometer over potassium 

hydroxide. The volume was between one and two cubic centimeters 

per gram of yttrialite. The gases were not further examined.

The analysis is.given above, together with that of Mackintosh for 

comparison. 

The ratios of Mackintosh's analysis as calculated above by me are 

certainly wrong in so far as they are affected b}7 the value for iron, 

which he assumed to be wholly ferrous. If corrected in accordance 

with the statement of my analysis, or, what amounts to the same thing 

for the purpose of illustration and is simpler, if my ratio is altered to 

conform to his statement for RO and.R2O3 bases, it becomes .0644: 

. 1882 a very close agreement.

It is altogether probable that Mackintosh's separations of the earths 

were not so far reaching as mine, and this belief is borne out by the 

differences in the experimental molecular weights for the lanthanum 

and yttrium groups, mine being more in accordance with what might 

be expected and, moreover, agreeing almost exactly with those which 

were found by me for rowlandite in 1893, namely, 336.8 and 266.2 

respectively^

It is of course impossible to say what disposition should be made of 

the small amounts of firmly held water, phosphorus, carbon dioxide, 

fluorine, and alkalies. The ratios of my analysis are', therefore, to a 

slight extent incorrect, but probably not enough to influence any 

conclusions that may be drawn. One thing is apparent, that the preliminary purification by acid has had no pronounced effect on the 

composition of the mass acted on, otherwise Mackintosh's and my 

analyses should show far greater differences in the main constituents.

The crude empirical formulas deducible from the ratios of the two 

analyses are nearly

Hillebrand ................. R"et E'"S88 R""47 (SiA)247

Mackintosh.................. R"B , R"' R""48 (Si a07L,

1)0 O I O !to \ fi i / 6±A

« The three minerals gadolinite, yttrialite, and rowlandite occur in Llano County in most intimate 

association, suggestive of close community of origin,.a suggestion which is emphasized by the marvelous agreement for gadolinite and yttrialite, not only in the relative proportions of the trivalent 

earth metals but in their absolute amounts as well.

Do ................................................................

Gadolinite (Enkins) .................................................

CeoQs .

2.65

2.66

2.62

3.07

5.06

La2 03 , etc.

5.22

5.01

5.22

5. IS

9.34

Y2 03) etc.

44.35

41.55

43.45

47.70

This concordant testimony of three analysts may be regarded as strong evidence of the correctness 

of the earth separations made by them in these cases. Nearly the same relation is shown by the 

trivalent earth-metals of rowlandite, as seen in the table above.
HILLEBRAND.] COMPOSITION OF YTTEIAL1TE. 67

there being a slight deficiency of oxygen atoms in each case for the 

radical Si 2 07 , which is increased by allowing for the C02 and P2 05 .

In so far then as the character of the acid radical is concerned the 

results of Mackintosh's analysis are fully confirmed, and there is 

absolutely no ground for accepting Benedicks's basic formula, which, 

as I have already shown (p. 62), is based on a palpable error. But 

the ratios are not at all such as to lend themselves to ready resolution 

into isomorphous salts of the acid Ii(i Si2O7 . By doing quite unwarranted violence to the analytical data the above formulas might be 

reduced to

R" R'"c R"" (Si,07 ) 4

which can be readity represented structurally as a single complex 

moleoule or as a mixture of molecules like 3R'"2Si 2 07 +R''R''''SioO7 . 

In neither case, however, is the t}^pe of the rowlandite moleoule 

approached, which requires an altogether different ratio of monoxide, 

dioxide, and trioxide bases; nor, if the second be accepted, is it at all 

clear that the.two molecules would be mineralogicaHy equivalent 

that is, isomorphous.

An alternative hypothesis is to regard the mineral as a mixture 

containing the anhydrous thorite .molecule. Proceeding on this 

assumption and deducting all thorium and uranium and the proper 

amounts of silicon and oxygen, the crude empirical formulas become

Mackintosh....................... R"6r, K'"87 , Si438 0 1001

flilJebrand .......'................ R"C1 E'i'886 SiM7 0 1M3

which may be interpreted as basic salts of metasilicic acid:

K"M R'"185 (R'"0)'187 (SiOs)4M

R", R'"m (R'"0)'1M (Si03 ), 7

or R" R'"3 (R'"O)'S (Si03 ) 7

this last being easily susceptible of symmetrical representation in 

graphic form.

On the whole, I prefer to leave the constitution of yttrialite unsettled 

until further evidence can be gathered, either from analyses of allied 

minerals or from yttrialite itself of more certain purity than any that 

has yet been discovered.

It must not be forgotten that the gases other than C02 contained in 

the mineral may be the cause of the inability to arrive at satisfactory 

conclusions in the case of this and all other minerals which contain 

them, as I have already pointed out on page 63.

My excuse for such a lengthy publication on a matter still unsettled 

is the desire to prevent general acquiescence in the grouping under one 

type of minerals which can by no means be regarded as proved to 

belong to that type, and to which yttrialite certainly does not belong.
68 CONTRIBUTIONS TO MINERALOGY. . [BULL. 202.

i SUMMARY.

The empirical formula of Hidden and Mackintosh for .yttrialite is 

confirmed, and it is shown that the basic formula of Benedicks rests 

on error and has no standing.

The formula of Hidden and Mackintosh is not, however, susceptible 

of representation as a simple salt of the acid H6 S1,O7 . On the purely 

hypothetical assumption of admixture of anhydrous thorite, the remaining constituents afford ratios conforming quite closely to those of a 

basic nietasilicate R" R'"^"^ (SiOs)7 .

It is shown for two reasons fully discussed that the formula proposed 

by Benedicks for thalenite is to be regarded as doubtful.
A PSEUDO-SERPENTINE FROM STEVENS COUNTY, WASHINGTON,

By F. W. CLARKE.

In the course of an investigation upon the ornamental stones of 

Stevens County, Wash., Mr. R. W. Thatcher and Prof. Elton Fulmer, 

of the State Agricultural Experiment Station, examined a supposed 

serpentine which proved to have quite anomalous composition. To 

the unaided eye the rock was ordinary serpentine of a tjrpical yellowish 

green color; it was fairly homogeneous, and capable of receiving a line 

polish. Incomplete analyses, however, by both of the above-named 

chemists showed that it was not serpentine, and as I had been consulted 

with regard to the interpretation of the data, a sample was sent to me 

for more exhaustive study.

According to Prof. S. Shedd of the Washington Agricultural College, Avho is conducting the investigation, the rock is from the quarry 

of the United States.Marble Company, 12 miles north and west from 

Valley, a station on the Spokane Falls and 'Northern Railroad. It 

outcrops on the face of a high bluff at an elevation of about 4,070 feet 

above sea level, and forms a wedge-shaped mass.cutting across the 

mountains in a direction 5° west of north. The adjacent rocks are 

slates, which lie conformably upon a very coarsely crystalline, dark, 

almost black, magnesian carbonate. The "serpentine" itself varies a 

good deal in color, and a series of samples in the United States 

National Museum show that the output of the locality is far from 

uniform. The}7 range from a white carbonate, through various intermediate mixtures of the verde antique type, to material which appears 

to be ordinary serpentine. The latter, however, as shown by the 

serpentine under consideration, is distinctly laminated in structure, 

and exhibits a splintery fracture. An analysis by Mr. George Steiger 

gave the following results:

8i02 .......:................................................. 13.08

' Al.,08 ......................................................... 1.63

Fe,03 - ----...-----.-.........-....---...----.--...----..----- 1.25

FeO.......................................................... .19

MgO ...... I......;.......................................... 56. 44

Cab......................................................... .33

H,0 at 100° ............................ ^...................., .85

H.2 0 above 100° .............................................. 23. 94

C02 ....:.................................................. 2. 03

99. 74

69
70 CONTRIBUTIONS TO MINERALOGY. - [BULL. 262.

These figures at once suggest a probable admixture of brucite with 

the serpentinous material, and a microscopic examination by Mr. J. S. 

Diller tends to confirm this supposition.

According to Mr. Diller the specimen is mainty composed of three 

minerals, a, 1), and c. The first two have nearly equal indices of refraction, but differ widely in birefringence. The mineral a is the 

most abundant. In transmitted light it is colorless, : but between 

crossed nicols it exhibits brilliant colors. The mineral 5 is pale green, 

and intermingled with a. Its birefringence yields weak colors, quite 

characteristic of chlorite. In quantity it is less than one-fourth of a.

Mineral c is granular, in scattered grains and irregular groups with 

a high index of refraction and a birefringence which suggests a carbonate, but it does not effervesce with a dilute acid. It amounts to 

not more than 5 per cent of the whole. Mineral 1) is certainly chlorite, 

and a may be brucite or possibly serpentine.

By appljdng Mr. Diller's observations to the analysis of the rock, 

the proximate composition of the latter may be deduced; although 

certain assumptions must be made. The carbonate present is probably hydromagnesite, for that species is a frequent associate of brucite. 

The composition of the chlorite is unknown, but it m&y be interpreted 

as essentially clinochlore, and as proportional to the ferric oxide and 

alumina. So much assumed, the analysis gives the following approximate results expressing the composition of the specimen:

Hydromagnesite ............................................... 5

Chlorite ....................................................... 14

Serpentine...................................................... 20

Brucite........................................................ 60

Extraneous water .............................................. .1.

Total .................................................... 100

In this, four minerals appear instead of three, but the microscopic 

examination did not attempt to discriminate between the brucite and 

the serpentine.

In order to obtain evidence confirmatory of the foregoing conclusions, a few experiments were made, tending toward fractional 

determinations. Upon digesting the powdered rock for two hours 

"with cold, dilute nitric acid (10 per cent by volume), 1.32 per cent of 

Fe2 03 +Al 2 0;j and 47.29 per cent MgO went into solution. In a similar 

experiment with cold, 20 per cent acetic acid, 0.69 Fe2 0;j +Al.,03 and 

45.64 MgO were extracted. Brucite dissolves readily in acids of the 

indicated strength, but some chlorite was evidently attacked as well. 

1 also found that ordinary serpentine was quite appreciably acted upon 

by weak acetic acid. These experiments, then, merely show that the 

rock contains a large amount of magnesium in a very easily soluble
CLARKK.] PSEUDOSEKPENTINE FEOM STEVENS COUNTY, WASH. 71

condition, the quantity equivalent to 60 per cent of-brucite being 41.4. 

The results are in harmony with the conclusions already reached, and 

help to support them, although accurate fractional determinations can 

not be made. The rock is unusual in character, and if the'sample 

examined is fairly characteristic of the entire deposit, the latter should 

be carefulty studied in reference to its origin and its geological 

relations.
ON "CALIPORNITE.'

F. W. CLARKE and GEORGE STEIGER.

.In 1901 Mr. G. F. Kunz a called attention to a remarkable massive 

variety of vesuvianite, discovered in California by Mr. A. E. Heigh - 

way, and which at first was thought to be jade. A second locality for 

the mineral, remote from the first, was found some time later, and 

here the vesuvianite was accompanied by another substance, which 

proved upon examination to be an unusual modification of garnet. 

For the vesuvianite Mr. Kunz proposed the varietal name "californite," and at first the garnet was supposed to be the same species, but 

different in color. Samples of all three minerals were sent to the 

laboratory of the United States Geological Survej^ for analysis, and 

the results obtained are given below. 6

A. Vesuvianite from the south fork of Indian Creek, 12 miles from 

Happy Camp, Siskiyou County, Cal.

B. Vesuvianite from Fresno County, Cal., 35 miles east of Selma.

C. White garnet, found with or near vesuvianite B.

Si02 ...... ......... .... ..................

AI A ......................................

Fe2 03 .....................................

FeO..... .................................

MnO.. ...................................

MgO......!.... ..........................

CaO.... ..................................

H2 0 at 105° ...............................

H.,0 above 105° ...........................

Ti02 1............... ....................

C02 .... .................................

P2 05 .....................................

F. .......................................

Less 0 = F ................................

Specific gravity ...........................

A. Vesuvianite.

. 35. 86

18. 35

1.67-

. .39

.05

5.43

33.51

.29

4.18

.10

.02

99. 85

B. Vesuvianite.

36. 55

18.89

.74

.74

2. 33

35.97 .

.58

3.42

.91

.13

100. 26 

.05

100. 21

3. 359

C.^ Garnet.

38. 59

22.24

4.K

.36

.10

.64

35. 97

.31

.80

.39

.17

100. 02 

.07

99.95

3.586

oMineral Resources U. S. for 1901, U. S. Geol. Survey; 1902, p. 747. Also, more fully, Am. Jour. Sci., 

4th ser., vol. 16, 1903, p. 397. 

& Analyses by George Steiger.

72
CI.AKKE AND")

STE1GEK. J ON '' CALIFORNITE. 73

These analyses .may be reduced to uniform type as follows: Throw 

out hygroscopic water, P2 05 , and C02 , with the equivalent amount of 

lime representing calcite. Recalculate Ti02 to equivalent Si02 ; Fe2 03

to A18 0S ; F(A MlA aud Mg° to Ca°> and F to HA Then recompute to 100 per cent. The reduced analyses are as follows:

Si02 . ..................

AlA ................'.

CaO....... ............

H2 0 ..................

Analyses.

A.

35. 58 

19. 24 

41.03 

4.15

100. 00

B.

37.28 

19. 74 

39.42 

3.56

100. 00

c.

' 39. 09 

22.82 

37.22

.87.

100. 00

Molecular ratios.

A.

0. 589 

.188 

.731 

.231

B.

0.617 

.193 

.703 

.197

c.

 0. 647 

.223 

.664 

.048

Analysis C gives the garnet ratios quite sharply, but as the mineral 

was white and massive, somewhat resembling chalcedony, its nature 

was at first unsuspected. Its density is that of garnet, however, its 

fusibility is the same, and in thin section under the microscope it is 

optically isotropic. It is undoubtedly garnet containing as an 

impurity about 1 per cent of calcium carbonate.

Analyses A and B are less easily interpreted. B gives approximately the empirical formula: 2H2 0, 2A12 03 , TCaO, 6Si.02 ; or. constitutionally, " . Al2Ca7 (Si04 )c (A10H) (A10.H,) H.

If part of the water is extraneous, the following much simpler 

formula may hold:

Al2Ca7 (Si04 )6 (A10H)2 ;

and this fairly represents a good many other analyses of vesuvianite, 

but not all. Vesuvianite varies in composition, and its variations are 

rather troublesome to interpret, for the}7 may signify either actual 

differences in the mineral itself, alterations, or impurities. The 

formula proposed by one of usft some years ago,

Al2Caf( (SiOJ5 (A10H),

is a good expression for the average composition of the species, but it 

does not fit the extremes. -

"Clarke, Bull. U. S. Geol. Survey No. 125, p. 25.
74 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

A careful study of over 40 analyses of vesuvianite leads us to suspect that it may be a mixture of several similar molecules, which we 

can represent .by the subjoined expressions:

Al2Ca7 (SiOJB (A10H)2 ,

Al2Ca7 (SiOJ6 H,,

Al2Ca7 (SiOJ6Ca2 ;

the first and third compounds usually predominating. Structural!}^ 

and with due regard to the analogy between vesuvianite and other 

species, these formulae may be written as follows:

Al-Si04= f » Al-Si04E= 

\SiO4 =R",

Ca Ca 

/Si04 =R". /SiO4 =R'a

About one-seventh of the calcium is replaced by magnesium, and in 

the variety wiluite the group BOH, analogous to A1OH, probably 

occurs.

Vesuvianite, then, is to be regarded as a basic orthosilicate, belonging to a group of compounds of which garnet is the normal salt. 

Epidote and the scapolites are other members of the same class, and 

their formulae are all strikingly similar to one another. As products 

of contact metamorphism they originate under like conditions, and 

they all undergo alteration in much the same wa}7 , yielding similar or 

even identical derivatives. Garnet, vesuvianite, epidote, and the 

scapolites must be considered together if the problem of their constitution is to be properly solved.
THE ACTION OF SILVER NITRATE AND THALLOUS NITRATE 

UPON CERTAIN NATURAL SILICATES.

By GEORGE STEIGER.

The following- investigation is practically a continuation of the 

experiments which were described by Clarke and Steiger in a recent 

bulletin of the United States Geological Survey/' although the new 

work is along somewhat different lines.

In the former research the alkalies and alkaline earth metals of certain silicates were replaced by ammonium, when the minerals were 

heated in sealed tubes with ammonium chloride. In the present work, 

silver nitrate and thallous nitrate have been substituted for ammonium 

chloride, the temperature employed being somewhat above their fusing 

points. As was anticipated, the alkalies and alkaline earth metals 

were replaced by the heavy metal, thus giving additional data relative to the constitution of the minerals.

The experiments were carried out as follows: The very finely ground 

material was mixed thoroughly with various amounts of nitrate by 

grinding in an agate mortar, the mixture was placed in a tube of Jena 

glass, and the tube was sealed. These tubes were then heated in a 

bomb furnace for the specified time and temperature, then opened 

and the contents leached with boiling water till the filtrate gave no 

test for nitrates. The residue was then dried and analyzed.

In a recent paper, 6 the writer gave the results of some preliminary 

work on analcite and chabazite.

Heumann 6' prepared a silver ultramarine b}^ boiling the native mineral with a solution of silver nitrate, and A. H. Church"5 made a silver 

phillipsite by allowing a solution of silver nitrate to act on the natural 

mineral at ordinary temperatures for almost three }7 ears.

For the optical notes in the present paper, the writer is indebted to 

Messrs. W. T. Schaller and J. S. Diller. -

The crystals in all cases were too small to permit a determination of 

their forms. A few optical observations were made, and Avith the 

exception of the isotropic compounds, it can be said that all were 

entirely crystalline.

(i Bull., U. S. Geol. Survey No. 207. «Lieb. Ann., vol. 199 (1879), p. 253. 

b Am. Jour. Sci., ser. 4, vol. 14, July, 1902, p. 31. rfMin. Mag., 1899, vol. 12, p. 9.

75
76 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

AJSTA:LCITE.

The analcite upon which the following experiments were made was 

well crystallized material from Table Mountain, near Golden, Colo.

Three silver derivatives were prepared as follows:

A. Ammonium analcite was heated in a sealed tube with four times 

its weight of dry silver nitrate for 4 hours at 250°-290° C., then 

leached with boiling water and the residue dried on the water bath.

B. The natural analcite was heated in a sealed tube with four times 

its weight of dry silver nitrate for 4 hours at 250°-290° C., then 

leached and the residue dried on the water bath.

C. Same as B, but heated 6 instead of 4 hours.

D. Analysis of the analcite upon which the experiments were made.

Analysis gave the results snown below:

Si02 ..................................

A1 2 0,----------. ---------------------

Ag2 0.. ...............................

CaO .................................

Na2 0 ................................

H2 0-.... ...........................

H20+. ......................... ....

NH............... ...................

In leach water: 

'Na.,0.... ....................

A.

42.69

18. 22

32. 01

.68

6.09

.69

100. 38 

.60

B.

41. 31

16. 44

37. 45

.85

4.29

100.34 

13. 13

c.

40.08

16.29

36. 91

.81

5.86

99.95 

12.57

D.

 55.72

23.06

.17

12. 46

.13

8.26

99.80

The products were all .perfect^ white, showing that no free silver 

oxide contaminated the residue. Under the microscope a small amount 

of the material showed double refraction-, but the larger portion of it 

was isotropic like the original mineral.

Residue A was boiled for. 15 minutes with a 5 per cent solution of 

sodium carbonate, and only a trace of silica passed into solution. With 

nitric acid the silver analcite gives sandy silica, and does not gelatinize 

on evaporation.

A portion of residue B was heated on the water bath for 2| hours 

with a 10 per cent solution of sodium hyposulphite and afterwards 

washed with water. In the residue 9.45 per cent of Na2O was found, 

showing that the silver salt had been converted back into the sodium 

compound, though not completely, the theoretical amount of Na2 0 

req uired being 14.1 per cent. Whether a hydrated salt had been formed 

was not determined. After treatment in a similar manner with potassium C}^anide 10.04 per cent of K8O. was found in the residue.
STKIGER.] ACTION OF SILVER NITRATE, ETC., ON SILICATES. 77

Considering the various amounts of alkali contained in the silver 

residues as unaltered analcite, deducting the equivalent amount and 

reducing the remainder to 100, the above analyses give the results 

shown below:" .

' 

8i02 . ..................... .,... ..'....

Al.,0, -------------------------- ------

Ag,0..... ...........................

H,0...... ...... .....................

. A.

40. 30

17. 27

36.65

5.69

100,00

B.

40. 28

15. 92

39. 78

4.02

100. 00

C.

39. 21

15.90

39.16

5.73

100. 00

Theoretical 

AgAl 

Si2 00 .H20.

39.35

16.72

38. 03

5.90

100. 00

For comparison, there is given in the last column the percentage 

composition of theoretical silver analcite. Residue B shows a deficiency of water, possibly owing to the use of too high a temperature in 

drying the powder before analysis. Residue C gives the following 

molecular ratios:

26Ag2 0, 24A1.A, lOOSiCX, 49H8O, 

agreeing well with the empirical formula

AgAlSi2 60 .H8 0.

Two thallium derivatives were prepared from the same lot of analcite, as follows:

E. Natural analcite was heated in a sealed tube with four times its 

weight of thallous nitrate, twenty-four hours at 250°-290° C.

F, Same as E, except that the heating was continued for fortyeight hours. The composition of the two leached residues is given 

below.

SiO, .....................................................

A1 2 03 ........................... ...'.......................

Tl,0..... .................. ..............................

Na20 .....................................................

1 1,0- ...................... .". ..........;:..............

H.,0+......... ...........................................

E.

34. 40

15.73

47.29 '.60

.62

.76

99. 40

F.

32. 66

13.62

'53. 01

.12

.20

.40

JOO. 01

« Iii these iuul all other deductions made in this work,the theoretical molecule has been assumed, 

in this case, NaAlSio00HoO.
78 CONTRIBUTIONS TO MINEEALOGY. [BULL. 262.

Both of the preparations were perfectly white. The microscopic 

examination showed thallium analcite to be mainly isotropic, with a 

few crystals having double refraction, as was the case with the silver 

derivative. The thallium compound is easily decomposed by nitric 

acid, giving sandy silica.

Deducting from analysis F analcite equivalent to 0.12 per cent of 

Na2O, and reducing to 100, the analysis becomes:

Si<V. ........................... .........................

Al 20a .....................................................

T1 2 0....... ..............................................

Residue F.

32.61.

13.60

53. 79

100.00

Theoretical 

TlAlSi 200 .

31. 33

13.32

55. 35

100. 00

In the second column is given the calculated percentage composition of normal thallium analcite. 

The molecular ratios of F are

24T12O, 23A12 03 100Si02 .

A closer agreement with theory could hardly be expected.

In the case of the silver compound, the one molecule of water of 

the original mineral has been retained, and it is essentially analcite 

with silver replacing sodium. It is not so with the thallium derivative, nor with the ammonium compound of'the former investigation. 

In both of these derivatives the water of the original mineral was lost, 

the formula being that of leucite with thallium or ammonium replacing potassium, leucite being a mineral closely related to analcite.

One crude experiment was made to show the action of lead nitrate 

on this mineral. Natural analcite was heated in a sealed tube with a 

10 per cent solution of lead nitrate for six hours at about 200° C. The 

composition of the washed and dried residue follows:

SiO......... ........... ....... ..............................

AlA .....................................................

PbO... ...................................................

Na20 .....................................................

H2 0..... ................................. ................

60.34

17.55

14.75

6.03

98.67

Molecular 

ratios.

100.0

17.1

6.1

9.7
8TEIOBB.1 ACTION OF SILVER NITRATE, ETC., ON SILICATES. 79

Water was not determined, but, as will be seen from the summation, it is an unimportant constituent of the compound. Evidently 

the anhydrous salt has been formed, but incompletely, for only about 

half the sodium had been replaced.

The molecular ratios are as follows:

6PbO, 10Na2O, 17A18O8 , 100SiO2 , 

or, combining the monoxide bases,

16RO, 17A12O3 , 100Si02 . 

In this a large excess of silica appears.

ILETJCITE.

The specimen of leucite at hand was impure, and more careful work 

was therefore deferred until some future time, when it may be possible 

to prepare an artificial mineral which will be studied in detail.

One preparation of the impure leucite was made by heating .the 

native mineral in a sealed tube with four times its weight of thallous o

nitrate for twenty-four hours at a temperature of 250°-290° C. The 

leached residue was dried on the water bath. The analysis of this 

residue follows.

sio, ..:.................................;._........:......

A1 20:) ......................................................

T1 2 0 ......................................................

K,0 ......................................................

H.,0- ...................................................

11,0+ ...................................................

'

Residue.

36. 00

16.32

42.77

4.26

.10

.20

99. 65

Molecular 

ratios.

100.0

26.7

16.8

7.5

1.8

Combining potassium with thallium, the analysis gives the following:

24(T1K)2 0, 27A12O3 , 100SiO2 , 2H2O.

This indicates that the same molecule has been formed as in the 

case, of analcite.

THOMSONITE.

The thomsonite used was well crystallized material from Table 

Mountain, Colorado. Only one derivative of this mineral was made. 

The thomsonite was heated in a sealed tube with four times its weight 

of dry silver nitrate, 20 hours, at 250°-290° C. The residue was dried 

at about 40° C. Its composition is given on the page following.
80 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

_". 

SiO, ................................................... -..

A1A ................-.......-.-...........-.-----.- .----:

Ag2 0 free .................................................

CaO......... '.'.-............ ............................. -

X&2 0. ............... .....................................

H2 0-.. ............ ....................................

H2 0+. .................................................

In leach water: 

CaO..-....................................,....:---.

Na20 ................................................

Natural 

thomsonite.

41.13

" 29.58

11.25

5.31

1.01

12.12

100. 40

Silver 

thomsonite.

33.80

23.21

23. 50

2.56

7.28

.71

.45

8.11

99.62 

2.68

5.04

The color of this residue was dark, showing that some silver oxide 

had been formed, so contaminating the salt. A determination of this 

free silver oxide was made by the following method, and it appears in 

the anal}^sis as "Ag2 0 free."

A portion of the silver thomsonite was weighed out in a platinum 

boat and placed in a glass tube, which was connected with a weighed 

calcium chloride tube; low red heat was then applied and at the same 

time a current of dry air was passed over it. At this temperature 

silver oxide is decomposed, liberating the entire amount of oxygen. 

The loss of weight in the boat was water plus oxygen, the gain in the 

tube was water alone; the difference represented the oxygen of the 

free silver oxide.

The new compound dissolves easily in dilute nitric acid to a clear 

solution, which forms a perfect jelly on evaporation. Under the 

microscope the material proved to be entirely crystalline, showing 

parallel extinction.

Deducting free silver oxide, and also the water lost below 100°, and 

reducing to 100 per cent, the analysis gives the results tabulated 

below:

8iQs ... ............. .....................................

ALA -----------------------------------------------------

AgaO. ....................................................

CaO..................................!...................

Na,0 ....................................................

H2 0... ................ ...................................

Silver thomsonite reduced.

' 34. 99

24.02

24.32

7.54

0.74

8.39

100. 00

Molecular 

ratios.

100. 0

40.3

is!o

23.2

2.1

80.0
STEIGER.J ACTION OF SILVER 'NITRATE, ETC., ON SILICATES. 81

The reaction here is incomplete, but the thomsonite ratios have 

been fairly well preserved.

As the water of this mineral is usually considered to form no part 

of the chemical molecule, in the following formula it has been represented separately.

For this and the two minerals to follow, the formulae proposed by 

F. W. Clarke have been adopted, regarding them as mixtures of salts 

of orthosilicic and trisilicic acids. The analysis gives the subjoined 

ratios:

18Ag2 0, 23CaO, 2Na2 0, 4:OA12 03 , 100SiOz , 80H2 0. 

Combining monoxide bases, we have

R"4SAl80Siloo0868 .80H,0; 

which gives a ratio of orthosilicic to trisilicic acid.s of

73Si04 : 9Si;)08 - 

. Substituting these, we have

R"43Al 80 (Si04 ) 73 (Si3 08 )»- 80H.O;

and combining the two acid radicles under the indiscriminate symbol X 

we have . ' 

R"13A180X88 .80 H2 0=1-2-2, 2H2 0.

The analysis of thomsonite reduced in the same way gives the formula

ir42AUSi04 ) 7B (Si3 08 ), 9SH2 0, 

or, condensed,

R"42Al85X84 .98H2 0=l-2-2, 2£H2 0.

CHABAZITE.

4> ' 

The chabazite used in the following work was the well crystallized 

flesh-colored material from Wassons Bluff, Nova Scotia.

Two silver derivatives, were made, as follows:

A. Ammonium chabazite was heated in an open tube with four times 

its weight of dry silver nitrate for six hours at 300° C.

B. Natural chabazite was heated in a sealed tub_e with four times its 

weight of dry silver nitrate for twenty-four hours at 250°-290° C.

Bull. 262 05 6
82 CONTEIBUTIONS TO MINEBALOGY;

C. Analysis of the original chabazite:

[BULL.2C2.

Si0.2 ..... ........................................

Ai£>3 . ..........................................

FeA--------- ----------------------------------

Ag2 0 ......................................... Oi

CaO.......... ........ '..........................

Na2 0......... ..................................

K.,0.------ --------------------------- ....

H3 0-. ............... ..........................

H,0+............ ..............................

N O

In the leach water:

AlA------ ' -. -- --- - -- 

CaO........................................

Na2 0 .....................................

A\

:-!8. 84

11.02

28. 95

B.

34.95

11.89

39. 63

.40

2.38

' 4.40

6.64

100.29

none

7.75

1.98

C.

50.78

17.18

.40

7.84

 1.28

.73

5.22

16. 63

100.06

This preparation was light in color, showing that no appreciable 

amount of free silver oxide could have been present. It was decomposed easily hy nitric acid, giving sandy silica.

The microscopic examination showed the material to be entirely 

ciystallirie and uniaxial.

In this, and as will be shown later in the thallium derivatives also, 

important amounts of N 2O5 have been retained. This is not due to 

incomplete washing, but the nitrate is firmly held within the-molecule. 

This same mineral gave, with ammonium chloride, a compound containing chlorine. What the presence of these small amounts of the 

acid radicles ma}'" mean .is not known, but in the following reductions 

N2O5 will be considered as combined directly with silver or thallium; 

the proper amount will be subtracted from the analysis.

Deducting water below 100° and also silver nitrate, analysis B 

becomes:

Si02 ......................................................

AlA .....................................................

Ag2 0.....................................................

Na2 0 ......................................................

H2 o. ...................'.......................:..... ....

Residue B.

45.30

15.41

33. 07

.52

5.70

100. 00

Molecular 

ratios.

100.0

20.0

19.0

1.1

42.0

X
8TK1GEB.] ACTION OF SILVER NITRATE, ETC., ON SILICATES. 83

. This gives the following molecular ratios:

19Ag2 0, !Na2 0, 20AL03 , 100Si02 , 42H2 0. 

Combining sodium with silver, we have

ir20Al40Si100 0280 .42H2 0. 

Hence the ratio between orthosilicic and trisilicic acids becomes

10Si04 .30Si,08 ; 

and combining them under the s}'mbol X, the formula is

R" 20Al10X10 .42H2 0=l-2-2, 2H2 0. 

Reducing the same way the analysis for chabazite, we have

R"20A140X40 .109H2O=1-2-2, 5iH2O. 

The two formula; are

Native chabazite ................... .R//lw Al40 (Si04 ) 1 o(Si 8 08 ) 8o.l09H!lO.

Silver chabazite..................... .R//,0Al40 (Si04 ) 10 (Si;(08 ).10 .42H,0.

Here calcium has been replaced by silver with a loss of three and 

one-half molecules of water.

The thallium derivatives were prepared with the same lot of chabazite. Two preparations were made, as follows:

D. Chabazite was heated in a sealed tube with four times its weight 

of thallous nitrate, forty-eight hours at 250°-290° C.

E. Treated the same as D, but heated for sixty-seven hours.

SiO,.. ........ .......................

A1A------- -" . -..- - 

Tl aO.... .............................

CaO. ................................

Na.2 0... ..............................

EIZ 0+. ..............................

HaO-.. .............................

NA ................................

In the leach water: 

A1A----------------------------

 CaO. ............................

Na»0...... ......................

Residue 

found.

28.92

10.75

51.58

.65

.28-

1.30

2.85

3.54

99.87

1.54

D.

 Residue 

red viced.

36. 31

13. 50

47.39

.81

.35.

1.64

100. 00

Molecular patios.

100. 0

21.8

18.4

2.3

1.0

14 7

]

Residue 

found.

29. 44

11.11

52. 11

.64

.35

1.53

2.60

2.50

100. 28

7.09

1.58

Residue 

reduced.

34.44

13. 00

49. 61

.75

.41

1.79

100. 00
84 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

Both of these residues were perfectly white and entirely crystalline. 

Thallium chabazite is easily decomposed with nitric -acid, yielding 

sandy silica.

Derivative D gives the following ratios:

1ST12O, 2CaO, !Na2O, 22A12 0.( , 100SiO2 , 15H3O; 

or, combining monoxide bases,

R"21Al 4iSi100 0287 .15H2 0. 

The ratio of the two acid radicles is

16SiO4 :2SSi;A; 

and, inserting these in the formula,, we have

R"MAl44 (SiOJ1 ,(Si,08 )M .15H8 0; 

or, condensed,

A rough experiment was made by heating silver chabazite in a sealed 

tube with a 10 per cent solution' of lead nitrate. The residue after 

washing and diying contained 5.59 per cent Ag2O arid 20.24 per cent 

PbO.

STILBITE.

The specimen of stilbite used came from Wassons Bluff, Nova Scotia. 

The action of silver nitrate upon this mineral was not investigated.

One thallium derivative was made by heating the stilbite in a sealed 

tube with four times its weight of thallous nitrate sixty-five hours at 

230°-280° C. The residue was perfectly white, entirely crystalline, 

and biaxial, and it gave sandy silica with nitric acid. The analysis 

follows:

Si02 ... .........................................

A1A--------"-----. ----- ---".- --- --- 

Fe,03 ..........................................

Tl.,0 ...........................................

CaO........ ....................................

NajO ................. :............ ............

H2 0-.. .................... ....................

H,0+... ........... ............................

Stilbite.

55.41

16.85

.18

7.78

1.23

^3.60

15.41

100.46

Residue.

36.75

11.74

42.94

.68

' .15

5.48

2.29

100. 03

Molecular 

ratios.

100.0

18.8

16.5

2.0

.3

20.8
STEIGER.] ACTION OF SILVER NITKATE,, ETC., OK SILICATES. 85 

Omitting- water lost below 100°, we have the following ratios:

16 T13 0, 2 CaO, 1 Na2 0, 19 A18 0S , 100 Si02 , 20 H2 0; 

and, combining monoxide bases,

' li"19 Al38Si100 0276 , 20 H2 0; 

which gives a ratio between the two acid radicles of

7Si04 :3lSi 3 08 . 

Inserting these in the formula, it becomes

R"19AlM (SiOJ7 (Si8 08 )ai.20 H,0,

which condenses to

 E"1_ 9A1 38XM .20 H2 0.

Reducing the analysis of stilbite in the same way, we get 

R" 17Al30 (Si04) 4 (S.i 3 08 ) S2 .93 H2 0=l-2-2, 5 H2O. 

From the last three minerals we get the following formulas:

Native thomsonite...............R//42 A]85 (SiO,) 7(i (Si.(08 )8-98H2 0=l-2-2,2^H.!0.

.Silver thomsonite ...............R//43Al80 (Si04 ) 78 (Sis08 ) 9 .80H 1!0=l 2 2,2EI 11 0.

Native chaba/ite ............... .R%Al40 (Si04 )i0 (Si308 )so- 109ia aO=l 2~2,5^H2 0.

Silver chabazite ................ .R%A] 40 (SiO.( ) 10 (Si;)08 ).i0 .42H2 0=l-2-2,2B._,0.

Thallium chaba/ite...............B//21Al4+ (Si04 .) 16 (Si 308 )!!8 .]5H20=l 2 2,Aq.

Native stilbite................... .R//17Al 3(i(Si04 ),(Si:tb8 ) 32 .93H2 0=l-2-2,5H,0.

Thallium stilbite ................R%AlM (Si04 ) 7 (SiB08 )sl.20H2 0=l 2 2, Aq.

The similarity of the foregoing formulas is plainly evident. Leaving water out of consideration, and except in the single case of silver 

thomsonite. the ratios agree closely with the ratios of 1-2-2 for the 

monoxide base, aluminum, and silicic acid. Jt will be seen that with 

the two silver derivatives, compounds retaining two molecules' of 

water were formed, although in the case of thomsonite a mineral 

hydrated with 2| molecules of water was taken, while the chaba/ite 

contained 5£.

NATRO LITE.

The natrolite which was studied came from Bergen Hill, N. J. 

Two silver derivatives were made, as follows:

A. Natrolite Avas heated in a sealed tube with a 10 per cent solution 

of silver nitrate, eighteen hours at 120° C.

B. Natrolite Avas heated in a sealed tube with four times its Aveight 

of dry silver nitrate, tAventy-two hours at 25.0°-2900 0.
86 CONTRIBUTIONS TO MINERALOGY.

SiO.,. ................................

A1 2 0, ..................... ..........

Ag2 0 free ............................

CaO.... .............................

Na2 0 ................................

H2 0. ................................

A.

40.45

10.24

1 20. 48

.93

7.84

B.

34.70

18.54

32. 30

3.91

2.50

.39

7.32

99. 66

B. reduced.

36. 25

19. 36

33. 73

2.61

.41

 7.64

100. 00

Molecular 

ratios.

100. 0

31. 4

24.0

7.6

1.0

70.2

Both preparations were very dark, showing that a quantity of free 

silver oxide had been deposited. The compound formed is easity 

decomposed by warm dilute nitric acid, giving a perfectly clear solution which gelatinizes upon evaporation. Under the microscope, it 

showed perfect crystallization.

Neglecting free silver oxide, residue B gives the following formula:

24Ag2O, SCaO, !Na2O, 31A18 03 , 100SiO2 , 70H2O, 

or, combining monoxide bases,

- B',.AlM Si 100 0M6 , 70H2 0,

which corresponds roughly to the formula K.2 Al2Si3Oi 0 . 2H2O. The 

ratios are not so good as could be desired, but are close enough to show 

that this compound has probably been formed.

One thallium derivative was made by heating natrolite in a sealed 

tube with six times its weight of thallous nitrate for forty,-eight hours, 

at 250°-290° C. The analysis gave the following results:

Si02 ........... ...... .....................................

A1A ............................................... ......

Tl.,0...... ...............................................

CaO...-................................................:.

Na2 0...... ..............................................

H2 0- .............................."......................

H2 0+.. ..................................................

Residue.

26.10

15.59

55.64

.67

.34

.51

.66

99.51

Molecular 

ratios.

100.0

35.1

30. 1

2.8

1.1

8.5
STKIGKR.] ACTION 0¥ SILVER TITRATE, ETC., ON SILICATES. 87

This compound is perfectly white. It is easily dissolved by dilute 

nitric acid, giving a perfect jelly on evaporation.

The optical observations were: Double refraction low, cleavage vertical, extinction parallel, probably biaxial. It was entirely crystalline. 

The molecular proportions are as follows:

30T12 0, 3CaO, !Na3O, 35A18 08 , 100SiO2 , 9H2 0; 

or, combining monoxide bases,

K'f, 8Al7flSi 100 0S39 . 9H8 0, 

which corresponds closely to the formula R2 Al 2Si3 010 .

SCOI/ECITE.

The scolecite used came from Whale Cove, on the island of Grand 

Manan, New .Brunswick.

One derivative was made by heating the .scolecite in a sealed tube 

with four times its weight of silver nitrate six hours at 250°-2SO° C. 

The residue was dried at about 35° C.

a\0i...... ....................... ..............

Al aO, ...........................................

Ag2 0 combined .................................

Ag2 0 free .......................................

Cao....... ..:............. .....................

Na2 0.. .........................................

HjO....... ....................................

1-1,0-1...........................................

Scolecite.

45. 86

25. 78

13. 92

.41

.40

13. 65

 100. 02

Residue. '

. 37. 28

21. 54

20.21

 6.67

5.40

.44

.46

7.92

'99.92

Molecular

ratios.

100. 0

34.0

14.0

15.5

, .1.1

70.8

..........

This residue was dark brown, owing to the silver oxide it contained. 

On heating over the low flame of the Bunsen burner in order to reduce 

the silver oxide to metallic silver it turned perfectly white.

On attempting to mount this preparation for microscopic examination the balsam became very dark, which prevented any optical observations from being made.

The molecular ratios for this derivative are:

14AggO, IGCaO, !Na2O, 34A12O3 , 100SiO2 , YlH2O, 

or, uniting monoxide bases, ' ' 

R'M AI M Si 100 0M8 , 71H.O.
88 CONTRIBUTIONS TO MINEKALOGY. [BULL. 262.

These proportions agree fairly well with the formula

R'2 Al 2 Si3O10 , -f-aq.

The reaction in this case was incomplete, only a little over one-half 

the calcium and none of the sodium being replaced, but the experiment 

shows that the desired molecule was partially formed.

MESOMTE.

The mesolite studied was a fine specimen of crystalline material 

from Ostero, in the Faroe Islands.

One thallium derivative was prepared by heating the mesolite in a 

sealed tube with four times its weight of dry thallous nitrate for 

eighty hours at 240°-280° C.

Its analysis and that of the mesolite follow:

Si02 .. ..........................................

Al O

TI n

CaO ............................................

Na,0 ...........................................

H ,0 ............................................ H,O+. .;.....................................

In the leach water: 

Al,03 . ......................................

CaO........................................

Na,0..... ..................................

Mesolite.

AX. t)7

25. 98

9.69

4. 79

1.34

12.04

99.81

Residue.

29. ll

16.94

44. 75

2.90

.26

3.32

3.06

100. 34 

None.

5.50

4.42

Molecular 

ratios.

100.0

CM 0

21.7

10.8

.8

35.0

..........

The leached residue was perfectly white and entirely crystalline, 

with parallel extinction. It gave a perfect!}7 clear solution with acid, 

which gelatinized on slight evaporation.

The molecular ratios are as follows:

22Tl2O,llCaO,lNa2 0,34Al2O;j ,100SiO2 ,35H2O. 

Combining monoxide bases, we .have

agreeing almost perfectly with the formula

R',ALSi,Oin .H 0
BTEIOER.] ACTION OF SILVER NITRATE, ETC., ON SILICATES. 89

These three minerals and their derivatives give the following comparison, when all the monad and dyad bases are united under li":

Native natrolite............................. E,//36Alfi(i ShooO,^. 72 H.jO

Silver natrolite .............................R"33A16!! Si 1000m. 70 H.jO

Thallium natrolite .."....................... .R^Al^ Si 10003.TJ. 9 H2 0

Native scolecite.............................R".,., A166 Si,000333 . 99 1:1 .,0

Silver scolecite.............. ; ...............R//S1 A1 68 Si 1000333 . 71 H2 0

Native mesolite. ............................R//33A](i(i Si 1000332 . 87 H.,0

Thallium mesolite ......................... .R//34A168 Sii00033fi . 35 H2 0

Since, as others have shown, the water in these three minerals plays 

no part in the chemical molecule, it has been placed as a separate constituent in the formulae.

The ratios found are not so sharp as could be desired, nor have the 

reactions been complete, but they indicate that the three minerals are 

all derived from the trisilicic acid H8 Si3 010 .

Deducting from each of the above formulae the water contained in 

the undecomposed mineral, which latter is represented by the amount 

of alkali retained by the derivative, we have the water contents: 

Silver natrolite ................... .70 H.2 0 less 18 H2 0 equals 52 H.,0

Thallium natrolite ................. 9 H 2 0 less 8 H2 0 equals 1 H2 0

Silver scolecite .....................71 H2 0 less 50 H.,0 equals 21 H2 0

Thallium mesolite .................. 35 H2 0 less 29 .1:1 2 0 equals 6 H2 0

We have here, as was the case with the thomsonite, chabazite, and 

stilbite derivatives, silver compounds strongly hydrated, while the 

thallium salts are practically anhydrous.

PECTOMTE.

The pectolite came from Bergen Hill, N. J. It contained a small 

amount of calcium carbonate as an impurity.

A single silver derivative was made b}7 heating the pectolite in a 

sealed tube with four times its weight of dry silver nitrate, for twent}^ 

two hours at 240°-2SO° C. The residue was dried on the water bath. 

On analysis the following results, stated below, were obtained.

sio......... .......................... :........

AW- .........................................

Ag2 0..................... .......................

CaO ............................................

MnO ...........................................

NaaO ...........................................

H,0...........................................

HS 0+...... ....................................

C02 ............. ...........................I...

Pectolite.

53. 34

.33

33. 23

.45

9. 11

.27

2.70

.67

100.10

Residue.

39. 05

.38

. 32.57

18. 13

5.99

4.12

100. 24

Molecular 

ratios.

100.0

. 21. 5

49.8

14.9

35.2
90 CONTRIBUTIONS TO MINERALOGY. [BULL.262.

The derivative was dark, but on heating over the bunsen burner 

the color, disappeared, and on treating the ignited residue with nitric 

acid red fumes were given off, showing that a quantity of free silver 

oxide was present. This was not determined, but is contained in the 

.figures given for Ag2O. The silver oxide reported is therefore several per cent too high.

The compound" is easily decomposed by warm dilute nitric acid, 

with the separation of sandy silica. A complex breaking up of the 

molecule has taken place and no simple ratios appear.

EI^EOUTE.

Elseolite from Litchfield, Me., was heated in the usual way with 

thallous nitrate. An incomplete analysis of the leached residue gave 

the following results:

Insoluble in nitric acid ............................ .......... 46. 34 

A1 208 ...............'....................................... 27.90

Tl,0 ....................................................... 8.50

Na2 0+K2 0...............^-.---........----..---.--.....-- 15. 40

Water, etc.................................................. undet.

in the leach water was found 2.13 per cent of sodium and potassium 

oxides. The analysis shows that elasolite is but slightty attacked b^y 

treatment with thallous nitrate.

JEGJRITE.

^Egirite from Magnet Cove, Arkansas,'was heated in a sealed tube 

with dry silver nitrate. The following results were obtained on analysis of the leached residue:

Insoluble in nitric acid...................................... 91. 22

Al a08+FeA............................................... 1.18

CaO ___..............-..-----.-......-.. .................. small

Ag80 ...................................................... 4.12

Na20 ...................... '. ............................... .53

Water, etc ................................................. undet.

This mineral has evidently been but little altered by the action of 

silver nitrate.
DUMORTIERITE.

By WALDEMAK T. SCHALLER.

INTRODUCTION.

Duraortierite was discovered by Gonnard" in November, 1879, at 

Chaponost, near Lyons, France, and was made the subject of a brief 

note by E. Bertrand in 1880. The following year, Gonnard named the 

mineral after Eugene Dumortier, the eminent French paleontologist.

The mineral was known to be new from its optical properties 

before its chemical composition was determined, its beautiful pleochroism being especially marked. Damour soon after made an analysis 

of the mineral, from which he obtained the formula 4 A12 0.( , 3 Si02 .

Specimens of. this mineral from New York, previously taken for 

indicolite, were studied by Diller and Jtiiggs and shown to be differ- 

,ent from tourmaline. At about the same tim6 dumortierite from Arizona became known, and analyses of the mineral from both localities 

were made. These analyses all showed the presence of boric acid in 

varying amounts, and also a small quantity of water. An occurrence 

of dumortierite in Norway was afterward noted, and still later several 

localities in Germany were mentioned.

In 1902, Ford published . three analyses of dumortierite, one on 

material from New York, a second on material from Arizona, and a 

third on material from a new locality in San Diego County, Cal. In 

the same paper he mentions a second new locality, the fourth one in 

this country, in Skamania County, Wash. He showed by his analyses 

that dumortierite contains boric acid and water in nearly constant 

amount.

A careful search for crystals was made in a large quantity of the 

California mineral, which resulted in the finding of two small, imperfect but measurable examples. On looking over the Arizona material 

in the National Museum a third crystal was found. Three crystals 

were also obtained among specimens from New York. These were 

carefully measured and some crystallographic data were thus obtained.

The mineral is usually sparingly present in small fibrous masses 

scattered through the rock, making it difficult to obtain an}^ considera For references see Literature, pp. 119-120, this bulletin.

91
92 . . CONTRIBUTIONS TO MINERALOGY. [BULL.262.

able quantity^of it in a pure condition. At the California locality the 

mineral occurs in large, pure masses, very favorable for chemical 

investigation. From an analysis made by the writer on the California 

material, a formula was deduced in which the boric acid and water 

have a certain fixed value. The other analyses are discussed, and it 

is shown that they all agree fairly well with the new formula proposed 

by the writer. An analysis of the Washington dumortierite is also 

given. Ford tested the French material qualitatively for boric acid 

and obtained a strong positive reaction.

While a more or less complete study of the mineral has been made, 

it is fully realized that in no sense can the work be called complete. 

The material for crystallographic study Avas poor, and it is very much 

hoped that better crystals will at some future time be found. The 

determinations of optical .constants are very meager, for the usual 

condition of occurrence of the .mineral is not favorable to such study. 

Only a few analyses are available for any discussion of the composition 

of the mineral, and though dumortierite does not contain a large number of constituents, many more analyses but only extremely accurate 

and reliable ones will be gladly welcomed.

It was found that the California material differed somewhat in its 

properties from normal dumortierite. The color is lavender instead 

of blue, the pleochroism is colorless to red purple instead of blue, and 

the mineral contains 1£ per cent titanium oxide. It is of especial interest to correlate these differences, as it adds another good example to 

that class of silicates which contain a small amount of titanium and 

(seemingly thereby) acquire a purple pleochroism.

OCCURRENCES.

FOREIGN. 

FRANCE.

Dumortierite a is found at several places in the vicinity of Lyons 

(Rhone), where it occurs in a pegmatite gneiss. At Beaunan, on the 

road from Oullins to Chaponost, it is found in a small quarry in gneiss 

in slender blue fibers in the midst of veinlets or lenses of feldspar and 

pegmatite. At Brignais it occurs in very small fibers disseminated 

throughout a white pegmatite, associated with large black tourmalines, 

garnets, muscovite, and cordierite, the latter being largely altered to 

mica. In some cases bluish tourmaline and dumortierite have the vertical axis in common. Fseudomorphs of mica after dumortierite are 

frequent. "

The mineral has a good, cleavage parallel to a {100} and an imperfect prismatic one. There are also "planes of separation" parallel to 

the base. Twins, analogous to those of aragonite, are frequent. The

"Lacroix, A., Mineralogie dc la Franco, vol. i, 1893-1895, pp. 15-19.
SCHAI.T.ER.] . DUMORTIERITE. 93

color is blue, sometimes nearly black. Inclusions are not prominent, 

though bubbles and rutile have been noticed.

The axial plane is parallel to &{010}. Bxa (negative) perpendicular 

to c {OOl}. In the twins the axial planes of the two parts make an 

angle of about 60°. ft is about 1.65, and the birefringence is about .010. 

The axial angle (2 VNlv) is near 35° to 40°. The dispersion is energetic p<v. Pleochroism is very strong; b = .c, colorless or very pale 

blue; l-X, cobalt blue or violet. Some of the specimens from Brignais 

are of a rose-salmon color, a little redder than andalusite. % The maximum absorption is (contrary to that of tourmaline) in the direction of 

elongation (parallel to c}. The presence of idiophanous figures is also 

noted. According to Daniour, the blue color of the mineral may perhaps be due to traces of Ti2 0;! , the presence of which in the French 

mineral has, however, not been demonstrated. It is noticed that the 

small fibers of dum.ortier.ite are often inclosed in a white mica, which 

is gradually replacing the original mineral.

GERMANY AND AUSTRIA.

The mineral is found near Schmiedeberg, Silesia," in the pegmatite 

of the lower Val Donbastone, in long fibers of a green or greenishblue color. These fibers have a thickness of 1 mm. and reach a maximum length of 50 mm. They are of ten. bent, and inclose pieces of 

quartz. On one fiber a prism angle of 69° 6' was measured. Prismatic cleavage, imperfect, was noted. The pleochroism is very strong: 

.C = .b, colorless; il, pistachio-green. Cross sections show the emergence of an acute bisectrix (negative), the axial angle being somewhat 

smaller than that of muscovite. With a crystal refractometer the 

following values for the indices of refraction were obtained:

«=1.67S 

/3=1.686

r=i.6S9

y-a- .011'

An analysis of impure.material was also made.

In a clayey residue, the mineral has been found at Iinligan, near 

Chodan, and Schobrowitz, near Carlsbad, in Bohemia, and in clayey 

sandstone at Oberbris, near Pilsen, in Bohemia. These residues are 

probably formed from decomposing pegmatite, from which the dumortierite originally came. The mineral shows a strong pleochroism; 

IX, deep carmine to smalt blue and, in places where partly decomposed, dark olive to red brown; It, light gray olive to colorless. The 

(negative) acute bisectrix is parallel to the elongation. The obtuse 

bisectrix is perpendicular to the cleavage plates (a={lOO|). The

«Soe Literature, pp. 110-120.
94 CONTRIBUTIONS TO MINERALOGY. ' [Buu,.2G2.

associated minerals are tourmaline, quartz, feldspar, muscovite, biotite, chrysoberyl, apatite, garnet, and chlorite.

NORWAY.

The mineral is found at Tvedestrand in minute fibers in cordierite 

gneiss. The pleochroisni is as follows:

jC = ft, pale yellow, almost colorless, 

a, intense cobalt blue.

Cross sections show a prismatic angle of about 60°. The birefringence (.010) is feeble. Pleochroic halos (in yellow) are very characteristic. The axial angle (2V) is about 35°, and the dispersion strong 

p >f. The associated minerals are cordierite and sillimanite.

Romberg lias described a mineral from Argentina (2.51 per cent 

B2O3 ) which seems to resemble the California dumortierite. The color 

is lilac and the pleochroisni similar to that from California.

UNITED STATES. 

NEW YORK.

The mineral occurs in that part of New York City known as Harlem. It has been sparingly found as acicular crystals " aggregated in 

fasces or tufts resembling clippings of hair" in a lode of red granite 

extending southeastward from Fourth avenue and One hundred and 

twenty-third street to Madison avenue at One hundred and sixteenth 

street. At One hundred and seventy-first street and Fort Washington 

avenue it was found in several pockets in a vein of coarse pegmatite 

in mica-schist. The vein is about 3 feet wide and the pockets extended 

for about 80 feet. The body of the vein is granular gra}r quartz, orthoclase, and flaky muscovite. The dumortierite occurs chiefly in the 

orthoclase, though it has also been found as long, filiform inclusions 

in the muscovite, singly and radiating from centers. It has also been 

noticed at Kips Ba}T , near the upper end of Riverside Park, in white 

oligoclase, and at Tenth avenue and One hundred and thirtieth street.

The associated minerals are orthoclase, quartz, muscovite, xenotirne, 

monazite, tourmaline, zircon, torbernite (?), antunite (?), apatite, garnet, and andalusite.

A brief study of several slides of the New York City dumortierite 

showed that the mineral occurs almost entirely in the orthoclase. 

Very rarely is it in the quartz or muscovite. It is usually in fibrous 

forms, with ragged outlines, and in one particular section an orthoclase crystal was filled with minute threads of dumortierite, arranged 

more or less parallel. In these slides andalusite also was noticed.

Mr. Frederick Braun, of Brooklyn, N. Y., very kindly lent the 

writer his private collection of Ne\v York dumortierite, which probably contains the finest dumortierite specimens ever found in that
SCHALLER.] DUMORTIERITE. 95

locality. About 25 specimens are shown, the best one containing a 

prismatic group of fine blue dumortierite fibers 5 cm. long and from 

one-half to 1 cm. thick. The rock is a pegmatitic gneiss, and consists 

chiefly of quartz and feldspar, with smaller quantities of biotite, muscovite, black tourmaline, dumortierite, and garnets. The dumortierite 

occurs in long prisms, often bent, and again broken, the space between 

being filled with the gneiss rock. The basal cross fracture is common 

and the color is often changed to a dull gray. At times the fibers are 

seemingly intergrown with the tourmaline in parallel position. The 

three crystals described later were obtained from these specimens.

As additional localities, Mr. Braun gives: One hundred and first 

street and Lexington avenue, New York; One hundred and eighteenth, 

One hundred and twentieth, One hundred and twenty-second streets 

and Madison avenue; One hundred and thirty-eighth, One hundred 

and thirty-ninth, One hundred and fortieth, One hundred and fortyninth streets and Mott avenue; One hundred and thirty-third, One 

hundred and thirty-fifth, One hundred and forty-ninth streets and 

Hudson River Railroad; One hundred and forty-ninth street and Sheerier place; One hundred and seventy-first street and Boulevard.

The mineral possesses a strong pleochroism, ranging from colorless 

to deep blue, this color being always in the direction of elongation. 

The extinction is parallel and the mineral orthorhombic. Cleavage 

parallel to the macropinacoid is perfect, these cleavage plates showing 

the emergence of an obtuse bisectrix. An imperfect cleavage parallel 

to the base is also noticed, and basal sections show an imperfect prismatic cleavage. Such sections show the emergence of an acute bisectrix. The mineral is negative. The axial plane is parallel to the 

brachypinacoid and .the orientation is a=£, b=Ii, c = a. The pleochroism is £=fr, colorless; a, deep blue. Absorption, a>fr=jc. 

Some sections show polysynthetic twinning lamellae, but their relation 

could not be made out.

ARIZONA.

At Clip, Ariz., dumortierite occurs in a quartz rock which lias not 

been found in place (Doctor Hillebrand), but only as loose bowlders. 

Dumortierite and quartz form the principal mineral constituents, kyanite, magnetite, and muscovite being present in subordinate amounts. 

The rock is fine grained and has a blue color due to the dumortierite.

Under the microscope, a section of the rock showed numerous 

small lath-shaped prisms of dumortierite placed in every direction in 

a mass of allotriomorphic quartz, with several large blades of muscovite and abundant magnetite, and a little apatite and rutile. Feldspar 

seems to be entirely absent.

The dumortierite has the usual colorless to blue pleochroism and 

presents normal properties. In the slide studied it is very fresh and 

shows no signs of alteration, the muscovite present being primary.
96 CONTRIBUTIONS TO MINERALOGY. [BOLL.262.

The quartz grains are (relatively) fairly large and are not crushed 

like those of the California rock. The rock seems to have undergone 

no dynamic change after its formation.

" The pale-green kyanite has been analyzed by Dr. W. F. Hillebrand 

with the results given below:

Si02 ......................................................... 36. 30

AlA(+Ti02 )'................................................ 62.51

' . Fe/V............................ 1....'.:.................... .70

FeO .... .................................................... unclet.

CnO......................................................... tr.

Ign ........................................, .................. .40

99. 91 

Specific gravity ........................................ 3.656 at 18.5

CALIFORNIA.

This occurrence was first mentioned by Ford, and an analysis of the 

dumortierite was given by him. The writer made a brief visit to the 

locality in the summer of 1903 and collected a large quantity of material, which permitted a rather complete study of the mineral. The 

writer's thanks are due to Mr. John A. Thoman, of San Diego, the 

owner of the property, for permission to visit the interesting locality 

and for the privilege of collecting specimens.

The mineral occurs in a dike a few miles east of Dehesa, San Diego 

County, and is not far from the orbicular gabbro described by Professor 

Lawson. 05 Tiie general country rock of the region is granite, in which 

occur large masses of gabbro, of which the orbicular rock is a peculiar 

phase. Both the gabbro and the granite contain many dikes, and it is 

in one of these dikes, in decomposed biotite-granite, that the dumortierite occurs. This dike has a length of about 1,000 feet and a thickness of about 30 or 40 feet, strikes S. 70° E., and has a dip of about 

70° N. 20° E. . ' The rock consists chiefly qf quartz and either sillimanite or dumortierite. Feldspar is entirely absent from the dike. The dike may be 

divided into an upper and lower part, according to the character of the 

rock. The upper part is fine grained and consists of quartz and sillimanite; the lower part is coarse grained and consists of quartz and 

dumortierite.

The upper part, forming about one-half the dike, is a fine-grained 

white saccharoidal rock, sometimes of-a grayish color, and never contains any dumortierite. It possesses a more or less schistose structure 

and cleaves off into blocks parallel to the dip. A little muscovite is 

sometimes present, small crystals of titanium oxide are abundant, and 

occasionally a little pyrite is seen.

a Bull. Dept. Geol. Univ. Cal., vol. 3,1904, pp. 383-396.
SCHAI.LER.] DUMORTIERITE. 97

Microscopically the rock is composed of allotriomorphic quartz, 

sillimanite prisms arranged in parallel bands (schistose structure), a 

little muscovite, probably secondary, and accessory titanite, titanium 

oxide, rutile (?), pyrite, apatite, zircon, and corundum.

The sillimanite occurs both as short and long prisms. The former 

are usually grouped together in parallel bands which may run across 

the entire slide or may pinch out at both ends, forming a very flat 

lens. The prisms are short and stout, usually more or less ragged in 

outline, with many transverse fractures. The several parts of a single 

prism thus broken are at times considerably 'displaced. Again, an 

entire row of prisms may be broken and displaced. The displacement 

is always in the direction of elongation of the prism. The ends are 

usually more or less rounded, and macropinacoidal cleavage is sometimes well developed. Some nearly square cross sections show diagonal cleavage. Titanium oxide and zircon are at times inclosed in the 

prisms. These prisms occasionally show slight alterations and at times 

seem to have been entirely removed, forming either an opaque mass 

or leaving just the outlines of former prisms behind.

The long, slender prisms are placed at all angles and are not grouped 

in bands as the others are. The edges are sharp and the ends are 

often terminated by two faces, forming a spear. These prisms are 

usually smaller than the others and decrease in thickness until they 

are so narrow as to become entirely opaque. These straight hairlike inclusions were at first taken for rutile or magnetite, but it is 

thought they are merely sillimanite prisms of extreme thinness.

Optically the two forms are identical, and are to be classified as 

sillimanite. The relief is distinct and birefringence is rather strong. 

The direction of elongation is always an axis of minimum elasticity. 

The crystals are nonpleochroic and always extinguish parallel. Pleochroic halos were not observed.

The quartz is allotriomorphic and is usually much cracked. In general the principal cracks are parallel to the bands of sillimanite, while 

cracks perpendicular to these bands are also numerous. Many transverse irregular cracks also occur. Some of the quartz grains seem to 

have been slightly displaced, and the cracks thus formed been filled 

with secondary quartz. Sometimes the bands of sillimanite have 

cause'd u augen" to form. In places the quartz shows large liquid 

inclusions, and strings of small inclusions, though not common, sometimes occur. Besides the inclusions mentioned and the accessory 

minerals, the quartz contains in places a large amount of very fine 

opaque dust, possibly magnetite. Such sections of the quartz as 

remain dark under crossed nicols show a uniaxial cross with a positive 

sign in convergent light.

Of the accessory materials, titanium oxide, probably rutile, occurs 

in the greatest abundance. A few grains are probably titanite, but 

Bull. 262 05 7
98 CONTRIBUTIONS TO MINERALOGY. [BUD,. 202.

the majority of the small sharply defined crystals are probably rutile. 

They .are at times slightly dichroic (yellow to brown), and occur an 

equidiametral ciystals. Some of the crystals in the bands of sillimanite have been crushed and lengthened out. In one case a ciystal of 

corundum was inclosed in rutile. Zircon is also widely distributed in 

irregular grains, usually of minute size. Occasionally a large piece 

has roughly the usual ciystal outline, but seems to have beeji more or 

less corroded. 'One large ciystal inclosed several small rutiles. The 

order of crystallization of the minerals seems to have been as follows: 

Corundum, rutile (and titanite), zircon, sillimanite, and quartz. It may 

be that there are two generations of sillimanite. Those long, slender 

sharp crystals in the quartz may have formed after the ciystals in the 

bands.

An analysis of the rock was made by the writer, giVing the results 

tabulated below: '

Si02 ...............................................'......... 75.54

A12Q3 ......................................................... 18. 65

Fe2 03 ........................,............................... .35

.....................................:............. .06

.................................................... none

................................................... .03

MgO

CaO

Alk

H2 0-

H2 0

TiOa

Zr02

PA 

FeS,

-1-

none

1.10

3.67

.48

.06

trace

.10

100.04

The large amount of water present is difficult to explain. The 

inclusions in the quartz account for some, and assuming the. presence 

of some water due to incipient alteration in the sillimanite, there is 

still a large amount unaccounted for.

.From the analysis, neglecting the water and accessory minerals, the 

composition of the rock is calculated as consisting of

Quartz. ...................._....._.,........................... 69

Sillimanite..................................................... 31

Deducting the water and other accessory minerals of the rock we 

obtaih the following comparison:

sio, ............ ....:.................................

A 1 O

Analysis 

recalculated.

80.3

19.7

Calculated for 

above 

composition.

80.5

19.5
SCHALLEK.] DUMOKTIEEITE. 99

As we approach the middle of the dike the rock loses its schistose 

structure, becomes coarser, and we find occasional masses of dumortierite, which are more and more abundant, until finally we come to 

what is called the lower part of the dike, consisting of abundant dumortierite and quartz. Very rarely a small black tourmaline or garnet is 

seen. Muscovite is more or less abundant throughout the entire 

lower part, and in places forms an«essential part of the rock.

The lower part of the dike differs in many ways from the upper. 

No schistose structure is apparent; the rock is very coarse and has a 

mottled appearance, due to the dark bunches 'of dumortierite on the 

white quartz background.

Some masses of dumortierite are very large, examples 5 by 3 by 3 

cm. being not uncommon. They usually have a radiated columnar 

structure and break off nearly parallel to the base in fairly plane surfaces, which on large pieces become somewhat bowl shaped. As the 

various libers are not strictly parallel but radiating, the breakage can 

only be approximate^ at right angles to the general elongation of the 

fibers. These masses of dumortierite weather from the rock and 

stand out very prominently. They usually have numerous cleavage 

cracks parallel to the base. The color of the mineral is lavender, 

resembling to some extent compact rubellite. Connected with this 

unusual color is the unusual pleochroism that the mineral possesses, 

being from colorless to red purple instead of blue.

The quartz is coarse grained and has a slight greasy appearance. It 

sometimes occurs in large masses free from dumortierite. Magnetite 

is present in small grains as well as titanium oxide rutile (?). An 

analysis of a sample of pure quartz was made to prove the absence of 

any feldspar or other silicate. The analysis follows:

Si02 ......................................................... 98. 78

Fe2 03 (total)................................................. .45 '

CaO ..i...... I............................................... .10

MgO ...........:............................................. none

Ti02 ......................................................... .61

P.j05 . ........................................................ trace

99. 94

A rarer phase of the rock consists of quartz, muscovite, and dumortierite, which is here present in small pieces but a few millimeters or 

less thick. The mica is here an essential constituent of the rock and 

in places becomes abundant.

Microscopically the minerals present in the lower part of the dike 

are seen to be dumortierite and quartz, with muscovite and sillimanite in small quantities, together with accessory magnetite, titanite, 

rutile (?), apatite, and zircon, as well as a number of small undetermined inclusions. The dumortierite occurs in irregular masses with 

ragged outline, often resembling in shape the hornblende of a diorite.
100 CONTRIBUTIONS TO MINERALOGY. [BULL.202.

Again, it forms fan-shaped radiating masses, sometimes of large size. 

Irregular broken fibrous masses also occur scattered through the slide. 

The quartz is allotriomorphic and is but slightly cracked. It is rather 

full of inclusions in places. With the exception of a little muscovite 

there are no secondaiy minerals present.

The common form for the durnortierite is shown in radiated fanlike 

masses that vary considerably in size. When the entire piece is larger 

than a quadrant, parts of the black cross (seen in spherulites) are seen 

when the nicols are crossed. These fan-shaped pieces are probably 

the results of an incomplete spherulitic growth. The most perfect one 

consists of but half a circle. On certain parts no radiated fibers are 

detectable, the (prismatic) cleavage lines being perfectly parallel. 

Some of the pieces become decidedly fibrous toward the ends, and the 

various individual fibers depart somewhat from true parallelism. In 

between these fibers fine-grained aggregates of muscovite can often 

be seen.

A number of pieces showed a (secondary?) growth of fibers, which 

are probabty in all cases dumortierite, as with high powers a faint 

pleochroism can be detected. They were at first thought to be sillimanite, but they agree in all their properties so far as can be determined with dumortiorite. These fibers can be classed in two parts.

Those in the first part seem to have been formed as a secondary 

growth on the main masses of dumortierite. The fibers branch out 

considerably and often form a radiating fringe around an entire section of the mineral. They penetrate the quartz grains, and interstitial 

muscovite is absent. The line Avhere they join the main mass of the 

mineral is usually fairly well defined. In general, the fibers are normal to the edge of the main mass, but locally they vary considerably, 

especially where they form fanlike groups.

The fibers of the second class clearly represent a stage in the alteration of the dumortierite to muscovite. The solid mass of dumortierite 

becomes fibrous and, at the edges, breaks up into small fibers, which 

gradual!}7 become loose from the parent mass. .The space where they 

formerly joined is now occupied by a granular mass of muscovite, 

which also fills the spaces between the fibers. Gradually this process 

goes on until, finally, we have a large mass of granular muscovite in 

which are embedded a few fibrous prisms of the original mineral. 

Fig. 6 shows diagrammatically a stage in the process. 

. Basal sections present an entirely different appearance. The macropinacoidal cleavage, so well developed on the New York mineral, does 

not show on the sections of the California mineral. The imperfect 

prismatic cleavage is present and divides the section up into a multitude of irregular bodies. Occasionally there is a short crack parallel 

to the brachj'pinacoid, and it may be that the mineral possesses an 

imperfect interrupted brachypinacoidal cleavage.
SCHAI/LER.l DUMORTIERITE. 101

The prismatic cleavage was found to be parallel to the prism {210J. 

A large number of measurements gave as the angle JOIO} A cleavage 

cracks 62°-67°, averaging 64°-65°. The angle JOIO} A {210} is 66° 01'. 

The cleavage cracks are irregular, and it was difficult to obtain any 

accurate measurements, but the ones made are sufficient to determine 

the cleavage. They were measured against the trace of the optic axial 

plane.

Poly synthetic twinning'lamella) were observed a number of times, 

and in one particular section (the same on which the prismatic cleavage was measured) were determinable to a certain extent. The 

alternate lamellre extinguished together, the difference in angle of 

extinction of two adjacent lame-line being about 31°. The line joining 

these lamella) is parallel to the cleavage or to the prism {210}. The 

trace of the axial plane is 

parallel (or nearly so) in adjacent lamella).

The pleochroism of the 

mineral is beautiful, especially if the section be not 

too thin. c=-a is colorless., 

ft= I is colorless to very 

faint pink, it= c is deep-red 

purple. None of the sections entirely possess the

ordinaiy blue pleochroism. 

In some slides, however, 

there are certain small areas 

of varied and irregular shape 

which do show the ordinary 

pleochroism. These small 

blue areas in the rich redpurple background make a most beautiful combination. On some 

sections a large area will have a faint bluish-purple color, as if intermediate between the deep-blue and the red purple.

This California dumortierite contains about 1| per cent titanium 

oxide, which is considered as Ti 2O3 , replacing part of the alumina. 

Correlating these facts with the other known instances, it seems as if 

the presence of the titanium controlled the occurrence of this purple 

pleochroism. Samples of the Washington and Arizona mineral, free 

from ^titanite and rutile, and which possess the ordinary colorless to 

blue pleochroism, were tested qualitatively for titanium with hydrogen peroxide, with a negative result in each case. One might conclude, 

therefore, that in those areas of a dumortierite section in which the 

color is blue there is no titanium; that they are molecular centers, so 

to speak, which are free from titanium. The absorption of the mineral

^"^t^HS^^':"'''- ".' n r-': '.-' '< .'j ' V- ' 

FIG. 6. Dumortierite altering to mnscovito.
102 CONTRIBUTIONS TO MINERALOGY. [BULL.262.

is a>lj»=.C. Optically it is negative, the acute bisectrix a being 

normal to the base. The axial plane is parallel to the brachypinacoid. 

The birefringence is higher than that of quartz, though only hy a 

small amount.

The sections of dumortierite show that inclusions are rare. The 

masses of mineral are usually pure, muscovite being about the only 

mineral included, and this is not strictly an inclusion, as it is a 

secondary product, forming along the fibrous cracks of the mineral. 

In one basal section a number of rutile (?) crystals were observed, but 

such inclusions are verv rare.

The quartz occurs in large allotriomorphic grains, but little cracked 

and sometimes almost free from inclusions and again thickly crowded 

with them. In no way does the quartz show the effect of pressure as 

the quartz of the upper part of the dike 'does. Occasionally when the 

nicols are crossed the color of a quartz grain will be somewhat 

banded, these bands occurring on several grains, being parallel 

throughout the entire slide. The inclusions are sillimanite, magnetite, 

rutile (?), and an undetermined mineral.

The rock composing the dike is doubtless an igneous plutonic rock. 

There would seem to have been an interruption in the stage of formation of the entire dike. The upper or sillimanite-bearing part was 

more or less completely formed when a mass was pushed into the place 

now occupied by the lower part of the dike. This mass exerted a 

great pressure on the already partly formed upper part, giving it its 

schistose structure. Boric acid in large amount was in the lower 

mass. Possibly it was a later intrusion and may have caused the 

increase in pressure of the lower mass, which gradually cooled and 

formed a borosilicate (dumortierite) and quartz. The absence of 

dumortierite in the upper part would seern to indicate that the addition of boric acid to the entire mass was a later incident, and had the 

original magna cooled without this extra intrusion the rock would 

have been uniform and would have consisted of an aluminum silicate 

(sillimanite or andalusite) and quartz. The intrusion of the boric acid 

could not change the character of the upper part, which had already 

(at least partially) formed, but it did change the character of the 

lower part. May it be that the pressure determined the formation of 

sillimanite instead of andalusite?

WASHINGTON.

Ford mentions this occurrence of dumortierite and gives as the 

locality "the headwaters of the North Fork of the Washougal River 

in Skamania County, Wash." Mr. Brereton, of Woodstock, Oreg., 

very kindly sent the writer a number of specimens, which form the 

basis of the following notes.

As Ford states, the dumortierite occurs in a new habit, being present 

as small spherulites up to 3 mm. in diameter. .
SCHALLER.] DUMORTIERITE. 103

The roc;k in which they occur is a light-colored, fine-grained rock, 

containing, besides the blue spherulites, patches of a compact, softj 

light-green mineral, shown to be uiuscovite. While the exposed surface of the rock is dark, the fresh portion light gray, rarely becoming 

almost white. Sometimes the dumortierite occurs so abundantly as to 

color the entire rock blue. Pjaite is also present and in places is very 

abundant.

Under the microscope the rock is seen to be very fine grained and 

to consist of quartz, muscovite, and andalusite in nearly equal proportions. The porphyritic spherulites of dumortierite form a striking 

feature in the fine-grained rock. The pale-green patches before mentioned are seen to be muscovite. Pyrite is abundant, and a few grains 

of magnetite (ilmenite?) surrounded by leucoxene are also present. 

In places the leucoxene is abundant.

The andalusite occurs as short laths with a square cross section and 

also as irregular more or less opaque masses without .definite*shape. 

They are probably in some stage of alteration, possibly to'muscovite. 

While usually very minute, the laths occasional^ become quite large 

relatively. In general, the andalusite surrounding the larger spherulites is much coarser than the main mass, though there are numerous 

exceptions. When clear and transparent, the laths exhibit the.normal 

properties of andalusite. The relief is moderate and the birefringence 

low. Imperfect prismatic cleavage is sometimes seen. The prisms 

are nonpleochroic and pleochroic halos are absent. Extinction is 

always parallel. The elongation is always in the direction of maximum 

elasticity.

Sillimanite seems to be entirely absent. Muscovite occurs in the 

green masses and also in minute particles distributed throughout the 

entire rock. Nowhere does it occur in plates, as it normally does in 

granite, but everywhere it is in minute pieces. .A good deal is probably derived from the alterations of the andalusite and dumortierite, 

and it may be possible that all of it is secondary that the rock originally consisted essentially of quartz and andalusite. An analysis of 

the green mineral was made on a small amount of material, containing 

also some andalusite and quartz. It shows the mineral is muscovite. 

thus corroborating the microscopic evidence. . 

SiOa ...............,........................:..-....:.....'... 50.13

A\fiA ....................i.................................. 32.37 

Fe.2 0;( (total) ..........-.................................;..... 1. 52

MgO ........................................................ .09.

CaO.....................................I................. .15

H20- .................................................... i. 1.74

H80+...................................................... 5. 08

KaO......:................................................. 9. 60

100. 68 

Specific gravity.............................................. 2. 80
104 CONTRIBUTIONS TO MINERALOGY. [BULL. 202.

The quartz occurs in allotriomorphic grains, which are so minute and 

so mixed with the andalusite and muscovite that recourse was had to 

chemical analysis to verify their determination as quartz.

The duraortierite occurs in small spherulites scattered throughout 

the rock and occasionally bunched together to form a large patch of 

blue. On an average they reach a diameter of from one-half to 1 mm. 

Their shape, while in general circular, is often elliptical and may 

become very irregular in places. They consist of fibers radialty 

arranged and show the optical phenomena of "spherulites." The 

duinortierite has parallel extinction, and its birefringence is somewhat 

higher than that of the quartz and also slightly more than that of

the andalusite, though the 

difference between that of 

the latter two minerals is 

very small.

The intensity of the pleochroism of the dumortierite varies,, so that in some 

spherules there are concentric bands of fibers differing 

greatly in the depth of their 

color. Some spherules are 

almost colorless, and it was 

at first thought they might 

be parallel growths of andalusite with the dumortierite, 

but such a conclusion could

Fto. 7. Forms of duinortierite. not be verified.

The fibers are not always

perfectly radial. They are at times gathered into "brushes," and a 

number of these put together may form a spherulite. The fibers are 

thus more thickly crowded in some places than elsewhere, and this 

frequently results in intensifying the pleochroism, so that in some 

spherulites there are numerous blotches of blue of much deeper color 

than the rest. Muscovite is frequently plentiful in a spherulite, being 

formed between the fibers, and is probably an alteration product of 

the dumortierite. Frequently a mass of dumortierite will be almost 

completely changed to mica, leaving but small fragments of the 

original mineral behind.

The fibers of dumortierite, while usually arranged radially, sometimes assume different shapes, and some of the masses of dumortierite 

seen under the microscope are reproduced in fig. 7.

Fig. 7 shows variations from typical spherulitic form that the fibers 

of dumortierite assume, a is four prisms irregularly joined at the
SCHAI.I.EK.] ' DUMORTIEK1TE. ' 105

center, the ends spreading out into ; 'brushes" of fine fibers. This 

form is fairly abundant. 1) forms a prismatic portion becoming fibrous 

at both ends, and while common in the New York, Arizona, and California occurrences, is a rare type for Washington dumortierite. c 

forms a sort of fan and is composed of several "brushes" joined together. It is a common type, d is an elliptical spherulite. e is a 

mass of prisms such as J, but not spreading out as a does. It is of 

rarer occurrence, f is a bunch of radial fibers with'no prismatic stem 

as in c. It is fairly common.

To confirm the microscopical determination of the minerals of the 

rock a chemical analysis was made by the writer of a fresh sample of 

the rock. The results obtained are shown below.

SiOs ........................................................ 57.18

Al,08 ....................................................... 34.10

Fe2 03 -...................................................... .54

FeO............................I........................... .28

MgO ....................................................... .10

CaO........................................................ .63

Na20...........-....-.......-..:.......................... .39

K,0......................................................... 2. 57

H,0-...................................................... .69

- H,0-|- ....... .............................................. 2.02

Ti02 ........................................................ .66

Zr02 .......................;................................ .02

CO, ........................................................ none

. P20& -------------------------- ..-.:.......---.... -....--. .53

FeS2 ........................................................ .28

MnO ....................................................... none

BaO ..... ..............................:................ .04

SrO .........:....................-....-.................... trace?

Li.2 0.-.--..---....-.------..-.-....-..-.-..-..-..-.-....-... none

100. 03

Out of 200 grams of rock, 4.3 grams of dumortierite were obtained. 

Some was doubtless lost, and the sample still contained some andalusite, but 2 to 2^ per cent would approximately represent the amount 

of dumortierite present.

The mineralogical composition of the rock is about as follows:

Andalusite..................................................... 35

Dumortierite. ................................................... 2

Quart/ ......................................................... 32

Muscovite ..................................................... 27

Accessories .................................................... 4

100
106 CONtEIBUTIONS TO MTNEEALOGY. '[BULL. 202.

The accessories consist of pyrite,' magnetite, possibly ilmenite, 

leucoxene, and apatite.. Considering the dumortierite as andalusite 

and calculating the soda in the anatysis as potash, we get the following 

comparison:

Si08 .....................................'...................

A1A .................................................... ....

KyO.... ...................... ............................

H,0....^... ............. .................................

Accessories. .................................................

Calculated 

composition.

57.66

33. 81

3. 19

1.22

4.12

100.00

Found.

57. ] 8

34. 10

3.16

' 2.02

3.54

100. 00

It is interesting to compare the minerals from the three western 

occurrences, where feldspar is entirely absent, and the rock in each 

case is composed (essentially) of the following materials:

Arizona: Dumortierite, quartz, muscovite, kyanite.

California : Dumortierite, quartz, muscovite, sillimanite.

Washington: Dumortierite, quartz, muscovite, andalusite.

As the three minerals, kyanite, sillimanite, and andalusite have the 

same chemical composition, the composition of the entire rock is"probably also similar.

CKYSTAI/LOGRAPHY.

While the writer was at the California locality he made special 

search for crystals of dumortierite, but is forced to the conclusion 

that good, perfect crystals of the mineral are yet to be found. A 

large quantity of seemingly promising material was collected and 

afterward carefully examined with a lens. One minute ciystal was 

found showing several fairly good faces in the prismatic zone and, 

when mounted on the goniometer, presenting minute terminal planes 

giving poor reflections. Further search afforded another crystal 

showing several prismatic faces but no terminations.

The collection of specimens of dumortierite from Clip, Ariz., in the 

United States National Museum, was examined, and on one specimen 

was found a small crystal showing two prism faces and a dome. Further, three small crystals were obtained from the New York mineral. On this poor material the following work is based. The results 

obtained are perhaps not accurate, but are the best that could be 

obtained. The California and New York crystals are long prismatic, 

while the Arizona crystal may be termed short prismatic.
SCHAU.ER.] DUMORTIERITE. 107

The mineral is orthorhombic, and from the various measurements 

the following axial elements have been calculated:

^=.6871

The crystals were measured with the two-circle goniometer, and the 

values for p0 and qm from which the above ratios are obtained, are

. ' #,= .7723 '

^=.6871

The forms observed are as follows:

J=0oo=010 

a= GO 0=100

=oo =110

?/ = 2oo=2]0

=\Q =102

2i

=o =203

Besides these forms, reflections were obtained from several other 

minute faces, but they were so minute, and the reflections so poor, that 

their validity is very questionable and they are omitted from the foregoing list. The averages of the measured angles, compared with the 

calculated values, are shown in the' following table:

Letter and symbol.

6 -Ooo -010 ...........................

a -co 0=100. .........................

I -co 2-120..........................

fj ifco =320. .........................

n =2cc =210. .........................

d =40 =102. .........................

v =|0 =203.... ......................

Measured.

</> 

0 /

0 00 

91 23 

29 19 

 49 01 

59 49 

65 23 

91 '21 

87 39

p0 /

90 00 

90 00 

90 00 

90 00 

90 00 

90 00 

21 46 

26 58

Calculated.

g>.

0 /

0 00 

90 00 

29 20 

48 20 

59 19 

66 01 

90 00 

90 00

p0 /

'90 00 

90 00 

90 00 

V 90 00 

90 00 

90 00 

21 07 

27 14
108 CONTRIBUTIONS TO MINERALOGY. [BULL. 2C2.

The brachypinacoid is present on four crystals, usually as broad 

faces. Some give relative^ good reflections.

The macropinacoid occurs on all crystals, except kthe one from Arizona, and always as narrow faces. The reflections were poor, but 

serve to identify the form. The ^ angles measured are as follows:

California ..................................................

Do ..................................................

Do .......:......... ."..:.............................

New York ........................................ .......

Do ...................................................

Do ...................................................

Measured.

0 /

90 02

93 46

90 00

92 57

91 15

90 16

Calculated.

0 /

. l '90 00

The brachy prism Z=oo2=120 occurs on four crystals as narrow 

faces giving fair reflections.

California .................................................

Do ...............:...................... ...._.......

Do ....................................................

New York ...... _.'................................_...._..

Do ...................................................

Measured.

o / 

30 00

28 00

29 22

29 34

29 39

Calculated.

o /

29 20

The unit prism is poorly developed on the California ciystals, 

being present but once as a narrow face giving a poor reflection. On 

the Arizona crystal it occurs twice as broad faces.

\

California ..................................................

Measured.

0 /

48 52

49 16

Calculated.

0 /

| 48 20
8CHALLKR.] DUMOETIERITE. 109

The macro prism g=%&> =320 is present Several times. The measured angles vary somewhat.

California, .................................................

Do ....................................................

Do ...................................................

Do ....................................................

Do ..................................................

 Do ...................................................

New York ................................................

Do ..................................................

Do ..................................................

Do ...................................................

Do ..................................................

Measured.

o /

58 55

59 42

60 36

59 38

59 23

60 .14

59 04

60 07

59 25

60 23

60 31

Calculated.

0 /

59 19

The macro prism ??.=2<x> =210 is present four times. The reflections were fair.

-

Do ...................................................

Do ...................................................

Do ...................................................

Measured.

0 /

65 26

65 35

65 19

65 12

Calculated.

o /

66 01

The macro dome cZ=£0=102 is present once on the Arizona crystal. 

The reflections were not very good.

The dome /y=fO=203 is present on one of the California crystals. 

The face is exceedingly minute and the reflection was poor.

On crystal No. 4 (New York) were observed two very small faces, 

giving poor reflections.

(1). ......................................................

(2)......... ............................................

<p.

0 1

( 83 46

I 83 16 

t 80 19

I «84, 17

p.

0 1

17 54

. 17 44 

16 50

17 28

These agree approximately with the symbol {8.1.20}, or considering 

the form vicinal to a dome, to {205}.
110 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

The combinations seen on the six crystals are as follows:

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6

New York .........................

New York .........................

 b, a, 1, , ,

 , d, I, -, -,

ff>

ff>

n, , v.

Fig. 8' shows three of the crystals. A is from California; size, 

1 mm. X i mm. B is from New York; size, 1 mm. X i mm. C is from 

Arizona; size, 1 mm. Xl mm.

The following table gives the calculation of the forms of dumortierite 

based on the elements given in this paper. The table corresponds to 

the forms given in Goldschmidt's Winkeltabellen.

a=.8897

c=.6871

lga=9.94924

lgc=9.83702

Iga0 =0.11202

Igb0 =0.16298

Igp0 =9.88779

Igq0 =9.83702

a0=1.2943

b0 =1.4554

pc =.7723

q0 =.6871

No.

1

2

3

4

5

6

7

8

Letter.

6

ci

I

m

ff

n

d

V

Syni-i

Miller.

010

100

120

no

320

210

102

203

gdt.

Oco

ceO

a.2

CO

% 

2oo

ifl

10

,

o /

0 00

90 00

29 07

49 01

59 47

65 23

90 00

90 00

Po /

90 00

90 00

90 00

90 00

90 00

90 00

21 07

27 14

foc /

0 00

90 00

90 00

90 00

90 00

90 00

21 07

27 14

V

0 /

90 00

0 00

90 00

90 00

90 00

90 00

0 00

0 00

f.

o /

0 00

90 00

29 07

49 01

59 47

65 23

21 07

27 14

,.

o /

90 00

0 00

60 53

40 59

30 13

24 37

0 00

0 00

x 

(Prism) 

x:y.

0

CO

.5570

1. 1510

1. 7170

2.1825

.3862

.5147

VCO

0

CO

CO

CO

CO

0

0

d=tgp.

CO

CO

CO

CO

CO

co

0. 3862

.5147

The minerals andalusite, sillimanite, staurolite, and dumortierite 

possess certain properties that are very much alike. They are all 

orthorhombic, their axial ratios are similar, their principal constituents are silica and alumina, and in many wa}^s these minerals can well 

be grouped together. "Using the word isomorphous in its general 

loose sense, these minerals are isomorphous. A comparison of their 

axial ratios is given below:

Andalusite .... r-.^ .......................... ..............

Sillimanite .............'...................................

Dumortierite ..............................................

d.

.9861

.970

.9795

.8897

6.

.7025

(?)

.6942

.6871
SUHALLER.] DUMOBTIEBITE. Ill

For staurolite the values are taken from Goldschmidt's Winkeltabellen with the a and c axes interchanged.

There was some question in the writer's mind as to whether the 

orientation chosen was the best or whether the present prism {210} had 

not better be made the unit prism. The cleavage is parallel to this 

prism, and the twinning also bears some relation to this form. Moreover, the ratio above given for staurolite, though adopted by Goldschmidt, is not, in the writer's opinion, the best one for the mineral. 

The one given by JDana, who makes the a axis just half as long, would 

be the better one. The common 

form of staurolite is prismatic, with 

a prism angle of 50° 40' (Dana).

For andalusite, on the other hand, 

the prismatic angle is 89° 12' and 

the a axis should be .9861, as given. 

Should dumortierite be classed crystal log raphically with staurolite or 

.with andalusite? Unfortunately, 

the evidence is almost too meager 

to decide this question. The .unit 

prism is poorly developed on the 

California crystals and entirely absent from the New York, the strongest form next to the brachypinacoid being the prism {320}. The 

prismatic cleavage is parallel to 

{210}, and making the cleavage form 

the unit prism the a axis should be 

given half its present value. On 

the other hand, the Arizona crystal is of the typical andalusite habit, 

and, making the prism the unit one, we obtain the axes as here given. 

Giving staurolite the (approximate) same axes as andalusite and 

dumortierite, the prismatic cleavage is parallel to the same form as in 

dumortierite {210}.

It may be worth noting that as staurolite and dumortierite are 

related crystallographically more closely than either with andalusite, 

the chemical composition of the two former is much more complex 

than that of the last named species.

PHYSICAL PROPERTIES.

GENERAL PROPERTIES.

Macroscopic crystals are exceedingly rare, the mineral usually 

occurring in prismatic fibrous forms showing no crystal faces. The 

Washington mineral occurs in spherulitic forms which are but a 

special arrangement of fibers.

FIG. 8. Dumortierite.
112 COJNTKIBUTIONS TO MINEKALOGY. [BULL.'262.

The cleavage is macropinacoidal good, prismatic {210} imperfect, 

and basal imperfect, and perhaps, also, in traces, brachypinacoidal. 

The New York mineral shows the macropinacoidal cleavage very well, 

while the California mineral shows the imperfect basal cleavage. The 

fracture is rough and the fibrous prisms are somewhat brittle, though 

a mass of fibers is very tough. The hardness is 7.

The following values for the specific gravity have been given:

3.36 

- 3.265 

> 3.22 

3.319

3.226-3.43 

3.211-3.302 '

Av. 3.292

The writer obtained 3.306 as the density of a piece weighing about 

10 grams. ' A good average value would be 3.30.

The luster is vitreous, somewhat satiny on the fibrous California 

mineral. The color is usually blue, though also lavender and. greenish 

blue to black. The colors noted are:

France: Blue, black.

Germany: Blue, bluish green.

Sweden: Blue.

New York, Arizona, Washington: Blue.

California: Lavender.

The mineral is usually opaque in its massive form, but the small 

fibers of the California mineral are transparent to translucent.

OPTICAL CHARACTERS.

All the determinations made on the mineral from different localities 

have given the same orientation. The axial plane is parallel to the 

brachypinacoid, the acute bisectrix is normal to the base. The mineral 

is negative.

The following are the pleochroisms noted on the mineral from different localities: Colorless to cobalt blue, pale yellow or colorless to 

cobalt blue, colorless to. pistachio green, colorless to rose salmon, 

colorless to deep carmine, colorless to red purple (California).

AXIAL ANGLES.

On the Norway mineral, 2VNa was determined as about 35°. Linck 

states that the angle is somewhat less than that of muscovite,
SCIIAM,KR.] DUMOKTIERITE. ' 113

The axial angle on the California dumortierite is small. The following measurements were made with the microscope and micrometer 

ocular, and represent on\y approximate values:

2Eu=33°

2ENa =37

2ECU =42

The dispersion thus is

INDICES OF REFRACTION.

Linck obtained for the dumortierite from Germany

«=1.678

/?=1.686

X=1.689

a y= .011

Michel Levy and Lacroix give (^ «) = .010 with the dispersion 

(strong) p>^, while Bertrand in his original description gives /><t> as 

the dispersion. The value (y a] for quartz is .009 and for andalusite 

.011. The birefringence for dumortierite is always a. little higher than 

that of the quartz, and in the Washington mineral very nearly that of 

the andalusite.

PYKOGNOSTICS.

The mineral is infusible before the blowpipe, but loses its color, 

becoming white. It gives a blue color on heating with cobalt nitrate. 

If the mineral be very finely powdered and intimately mixed with 

potassium bisulphate and calcium fluoride and the powder be carefully 

introduced into the flame, a green color, due to the boric acid, may be 

momentarily seen, but it is an exceedingly difficult reaction to obtain.

CHEMICAL COMPOSITION.

In 1881, after the first announcement of the discovery of the mineral 

.had been made by Gonnard, Damour gave the following analysis of 

the mineral:

SiO,. .....'................................................... 29. 85

Al A ........................................................ 66. 02

Fejp8 . . f .............. ....................................... 1 . 01

MgO ................ ......................................... .45

Jgn.............. ....... ................................... 2.25

99.58 

Specific gravity ...! .. ..:......................... 1 ..... 3. 36 

From this analysis the formula 4Al2 03 ,3SiO2 was calculated. 

Damour did not suspect the presence of boric acid in the mineral, and 

what was weighed, as alumina probably contained several per cent

Bull. 262 05 8
114 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

B2O3 . In 1887 Riggs gave an analysis of the New York mineral, in 

which he found 4 per cent B2 03 . Two years later Whitfield gave 

several analyses of American dumortierite, all showing the presence 

of B2 03 . In 1899 Linck gave some observations on the mineral, 

including an analysis by W. Schimpff, showing a strong test for boric 

acid. In 1902 Ford gave us three analyses of American dumortierite 

and also mentioned two new localities. During the winter of' 1903-4 

the writer made an analysis of the California dumortierite collected by 

himself during the previous summer. An anatysis was also made at 

the same time of the Washington dumortierite kindly furnished by 

Mr. Brereton.

Believing that one good analysis is better than -several poorer ones 

for the exact determination of the formula of the mineral, there will 

be presented an ariatysis of the California dumortierite made by the 

writer. From this a formula has been calculated for the mineral, 

and it will be shown how the other analyses agree with this proposed 

formula. Before giving the results a few preliminary words will not 

be out of place.

An analysis of dumortierite is a difficult operation. The small 

amount of silica makes it difficult to get a good fusion. On preliminary trials on an analysis of the California dumortierite, it was found 

that what was weighed as silica in the regular course of ^the analysis 

contained more or less of the undecomposed mineral. Results of 

about 30 to 32 per cent were obtained. This is, of course, on the 

unconnected silica. It was found that a second fusion of the supposed 

silica was not only very beneficial, but also necessary. What was 

then weighed'as silica contained but little residue. The handling of 

so large an amount of alumina is very cumbersome, and an accurate 

determination of the alumina (plus iron and other oxides here precipitated) is difficult. The boric acid determination is tedious and 

difficult. The accurate determination of the water, which is given off 

only at a high temperature, is also not eas}7 . One can thus see that 

an analysis of such a mineral is a troublesome operation and that a 

greater allowance must be made than for most silicate analyses.

The specimen analyzed was selected in the field, an exceedingly 

pure piece weighing about 10 grams being chosen. The specific 

gravity of this piece was taken by suspension in water, giving 3.306. 

This was broken into small pieces and carefully examined for muscovite, quartz, or other minerals. Sections of the mineral sh:wed that 

the dumortierite was free from any inclusions. No grains of &ny titanium mineral abundant in the quartz could be detected. When the 

mineral was powdered it was treated with heavy solution, of specific 

gravity 3.10, and a minute amount of mineral (muscovite?) sta}7 ed on 

top and was removed. The separation was repeated several times, 

and the powder was dried at 100° and carefully examined under the
SCHALIjER.], DUMOBTIERITE. 115

microscope for impurities. None was found. The mineral was 

unquestionably pure.

The general analytical methods used were those pursued in the 

Survey laboratory for silicate analyses, with a few modifications. The 

mineral was fused with sodium carbonate, the silica separated and 

re-fused with sodium carbonate. The silica was filtered off, weighed, 

and treated with HF, which left some residue. The alumina (plus 

iron and titanium) was precipitated three times to be sure of removing all of the sodium salts. It was ignited and weighed with the 

silica residue, fused with sodium bisulphate, some silica recovered, 

the iron was reduced and determined by titration and the titanium 

was determined colorimetrically. The presence of titanium was suspected from the color of the pleochroism of the mineral. The boric 

acid was determined l>y the Gooch method, using all of the known 

precautions. The mineral was twice fused with sodium carbonate and 

the boric acid was finally weighed as calcium berate.- The water was 

collected in a calcium chloride tube, the mineral being heated in a 

Gooch tubulated crucible in the usual manner. A blank determination was run before and after each water determination and a small 

correction applied. All possible precautions were taken throughout 

the analysis, which was made in duplicate. The results are given 

below. 

"

SiO............................ ........... ..--,'.........

A1 2 0, .................................................

TiA ................................................

FeA----- ............................................

Hs,0. . ................................................

BA .................................................

l.

28.58

«Q 01

1.49

.21

1.53

5.21

100. 33

2.

28.78

63. 30

L40

.25

1.51

5.53

100. 77

Average.

28.68

63. 31

1.45

.23

1.52

5.37

100. 56

The titanium is regarded as present asTi2 03 , replacing the alumina. 

Combining the alumina, titanium, andiron, the following ratios are 

obtained:

Si02 ...................................................... 5.94 or 5

Alj,0s ..................................................... 8.00 8

B2 03 ----------- ----------------------------- -------- .--- 1-06 1

H2 0..........................................(.........:. .96 1

The formula for dumortierite then is

8A12O3 , 1B8O8J 1H8 0, 6SiO2 .

It.has not been proved that either boric acid and alumina or boric 

acid and hydroxyl may mutually replace each other in minerals as fluor-
116 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

ine and hydroxyl are known to do. There is, then,'no reason that the 

writer can see why the alumina, boric acid, and water in dumortierite 

should not be present in fixed quantities, and that the variations 

shown in analyses are not due to " isomorphous replacements," but to 

inaccuracy of analyses or impure material.

Having established the above formula from the analysis, let us see 

how closely the other analyses conform to it. ;

The best series of analyses is that made by Ford of mineral from 

three American localities. His first analyses of the Arizona material 

are tabulated below.

SiO,. ........................................

A1A ........................................

Fe,0 . ..................,..""........:..........

BA--------- -.-- -.----. ..--.-

HtO.. ................. ........ .....'...... ..

 . ... _» .. . _.. .. 

i.

30.00

63.20

.23

5.47

1.45

2.

29.66

63. 74

.23

5.06

1.38

3.

29. 91

63.76

Average.

29.86

63.56

.23

5.26

1.41

100. 32

The ratios calculated from the average analysis give

SiO,.......... I..................................... 6. 29 or 6X1- 05

ALA .............................................. 7.94 8X .99

, BA----------------^------ ----------------------- .96 IX .96

H2 0 ................................................ 1.00 1X1.00

The agreement with the proposed formula is perfect.

His second analysis, that of the California mineral, shows slight 

variations from' the results obtained by the writer. The presence of 

titanium was not determined. His analysis is:

SiO,.. .............. I.............................

AIA ---------------------------------------------

Fe A .-.--.---.....---..---.......-....-..-.----.-

BA .............................................

H,0.-- ---------------------------------- --------

30.58

61.83

.36

5. 93

' 2. 14

100. 84

Ratios.

6. 17 or 6 XI. 03

| 7.40 8X .93

1.04 1X1.04

1.45 1X1.45

The ratio's agree well with the new formula except for the water 

content. Remembering, however, that the amount of water present 

is very small and that a difference of 0.10 per cent, would make a 

large difference in the ratios; that Ford determined his water b}>- igniting the mineral with lime,, thus not weighing the water direct^; and 

that the writer obtained only 1.52 per cent on the same mineral from
8CHALLER.] DUMORTIERITE. 117

the same locality, it seems much preferable to regard the determination of the water in Ford's analysis as too high rather than to 

attempt an explanation of it by the assumption of "isomorphous 

replacement, etc."

Of the.third analysis by Ford of the New York mineral, he says: "It 

is fully realized that the results are not to be looked upon as being as 

exact as those of the other analyses."

His analysis is:

SiO................. ..............................

Al A .............................................

FeA- --.......-.....-.. ..............--..--..---.

BA----------------------------------------------

H,0.----- ----------------------------------------

31. 24

61.26

.10

6.14

2.09

100. 83

Ratios.

6. 23 or 6X1. 04

7.23 8X .90

1.06 1X1.06

1.40 1X1.40

Assuming-that his water content is somewhat high, the ratios agree 

well with the new formula.

This concludes the list of anatyses of dumortierite which were made 

on pure material and with due knowledge of what was to be determined. 

A number of other analyses will now be given, which serve in a general way for the determination of the composition of the mineral, but 

can not be relied on for exact results.

One, which has heretofore not been published, was made by the 

writer on the Washington dumortierite. About 200 grams of the rock 

was powdered, and by repeated separation with heavy solutions about 

4 grams of dumortierite were obtained. The sample was by no means 

pure. It was found impossible to remove all the andalusite, an unknown 

but small amount remaining. It was found during the course of the 

analysis that the samples also contained some titanite (leucoxene) and 

a very small amount of pyrite. The analysis was made with all the 

care possible, and the following results were obtained:

SiO, ..............................................

A I a0, .............................................

FeA----- ----------------------------------------

TiOj, ..............................................

H20. ............................. ................

BA---:--~ --------------------------------------

C;iO..... .........................................

28. 51

59. 75

2.48

.95

2.12

5.54

.68

100. 03

Ratios after deducting titanite.

5.97or6x0.99

| 7.80 8X .97

1.53 .1X1.53

1.03 1X1.03
118 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

Excepting for the high-water content the analysis agrees very well 

with the formula. No allowance was made for the small amount of 

andalusite present, which would slightly alter the ratios.

The analysis by Schimpff of dumortierite from Germany is given 

below. Obviously it is worthless for an}^ calculation.

Si02 ......................................................... 36. 81

A12 0S ........................................................ 57. 27

CaO......................................................... 1.66

MgO .......................................:................ 1.38

Ign ................................:......................... 1. 31

B203 ................................................... strong test

98. 43

Of similar character is Jannasch's analysis of the Argentine mineral. 

The sample was probably very impure.

Si02 ......................................................... 35. 01

B203 ..........:............................................. '2.51

TiOj (Ti 2 03?) ----- .--...--...-...........-.--..--...-.----.- 1.08

A12 03 ....................................................... 51.49

Fe2O3 ........................................................ 1. 04

CaO............'.....................................,....... .28

MgO ....................................................... .54

K2 0......................................................... 3.62

Na2 0..............:......................................... .96

H20......................................................... 3.02

99.55 

Specific gravity ...................... ........................ 3.255

There now remain the analyses of Whitfield and Riggs, of which 

but one is suitable for any calculation. The analyses are as follows, 

No. 1 being of the New York mineral, by Riggs; No. 2 of the New 

York, and Nos. 3 and 4 of the Arizona mineral, by Whitfield.

i.

Si02 . 

Al,03 

MgO. 

K2 0 . 

Na2 0

Ign

34.82

55.30

.57

31. 44

68.91

1.04

1.76

4.07 

2.-96

100. 52

trace

100.33

31. 52

63. 66

.52

.11

.37

2.62

1.34

100.14

27.99 

64.49 

trace

 .20 

4.95 

1. 72

99. 35
SCHALLEB.] DUMORTIERITE. 119

The ratios of the last, analyses are

Si02 . ................................... ............ 5. 94 or 6X0. 99

A12O3 . .............................................. 8. 09 3X1. 01

B2O3 ............................................... .80 IX . 80

H2O......................... ....................... 1.22 1X1.22

Approximately they agree with the formula.

The only question of which there seems to be any doubt is whether 

the water should he 1 or li molecules. As, however, the best an-atyses 

show but 1 molecule and their evidence is considered as of much more 

value than a larger number of inferior analyses, there is no question 

in the writer's mind but that the formula for dumortierite is

SA12OS , 1B2O3 , 1H2O, 6SiO8 . 

This may be written

(SiO4),Al(AlO)7 (BO)H,

f 

which is the same as the formula given by Groth except that for (BO)

he puts (A1O). ; His formula is (SiO4) 3Al(AlO) 8H. " 

This formula maj^ be written in the following form:

Si04=(A10)3

SiO4 A1O 

\BO 

\H

This formula is similar to that of andalusite, which is written

8i04=Al 

SiO4==Al

SiO4=(AlO) 3

Dumortierite alters to muscovite. The change can be verjr well 

shown by these formulae, and seems to be entirely in accordance with 

the.group of minerals to which it is related.

Dumortierite. Muscovite.

SiO4==(AlO), SiO4=Al

AleSiO i/cur* '4=(AlO)s =

+alumina and boric acid set free. v SiO4 A1O SiO4 K 

\BO \H, 

\H

LITERATURE.

BERTRAND, EMILK. Sur un mineral bleu de Chaponost, pres Lyon. Bull. Soc. Min., 

vol. 3, 1880, p. 171.

GONNARD, F. Note sur 1'existence d'une espece min^rale nouvelle, la dumortierite dans le gneiss de Beaunan, audessus des anciens aqueducs gallorouiains de la 

vallee de 1'Iseron (Rh6ne). Ibid., vol. 4, 1881, p. 2.
120. CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

DAMOUR, A. Analyse de la dumortierite. Ibid., vol. 4, 1881, p. 6.

BERTRAND, EMILE. De 1'application du microscope ii 1'etude de la mineralogie. 

Ibid., vols. 8 and 9, 1881.

BIGGS, R. B. Am. Jour. Sci. (3d ser.), vol. 34, 1887, p. 406.

CHAMBERLAIN, B. B. Trans. New York Acad. Sciences, vol. 7, 1888, p. 211.

MICHEL-LEVY, A., and LACROIX, A. Comptes Rendus, pp. 106, 777, and 1546, 1888.

GONNARD, F. Sur un nouveau gisement de dumortie'rite a Brignais (Rh6ne). 

.Bull. Soc. Min., vol. 11, 1888, p. 64. . .

DILLER, J. S., and WHITPIELD, J. E. Dumortierite from Harlem, N. Y., and Clip, 

Ariz. Am. Jour. Sci. (3d ser.), vol. 37, 3889, pp. 216-219. Also Bull. TJ. S. Geol. 

Survey, No. 64, 1890, p. 31. ' '

GONNARD, F. Sur un nouveau gisement de dumortierite dans le Rhone. Bull. 

Soc. Min., vol. 15, 1892, p. 230.

ROMBERG, J. Petrographische untersuchungeii an argentimschen Graniten. ^Neues" 

Jahrbuch, Beil. Band. 8, 1893, p. 340.

HOVEY, E. O. Bull. Am. Mus. Nat. Hist., Vol. 7, 1895, pp. 341-342. .

LINCK, G. Die Pegmatite des oberen Veltlin. . Jenaische Zeitschr. f. Naturwiss., 

vol. 33, 1899, pp. 345-360. Ref.: Zeit. f. Kryst., vol. 35, 1902, p. 319.

ROSLER, H. Ueber Hussakit (Xenotim) und andere seltene gesteinbildende Mineralien. Zeit. f. Kryst., vol. 36, 1902, p. 262.

FORD, W. E. On the chemical composition of dumortierite. Am. Jour. Sci. 

4th ser., vol. 14, 1902, p. 426.
MINERALOGICAL NOTES.

W. T. SCHALLER.

1.

The pink clay occurring at Branchville, Conn., has been shown* to 

be montmorillonite, while that occurring at Norwaj7 . Me., has proved* 

to be cimolite. That from the lepidolite mine near Pala, San Diego 

Count}', Cal., differs from both of the New England clays, being 

comparable with halloysite.

At Pala the halloysite occurs in large seams, often several inches 

thick, and many feet in length. The clay is somewhat moist, but 

quickly dries to a crumbling mass when taken out of the mine. In 

color it is rather deeper pink than the Norway cimolite and occasionally is somewhat translucent. It readity crumbles to a fine powder 

when placed in water. The material analyzed had been drying in the 

air for over three months.

The results of analysis are shown below.

SiO2 ..................................................:..... 43. 62

A1,OS ... I................................................... 35. 55

Fea O3 . ................................^..:................. .21

MnO ....................................................... .26

CaO..................................................I..... 1. 02

MgO ....................................................... .19

Li2O......................................................... .23

Na.,0 ....................................................... .19

K2O.............I...................'......................-. .03

H2O (107°) ................................................. 6. 63

H2O (above 107°)........................................... 12.25

TiO2 -._..._..._....-.._..__..-----..-----.-----.------...-.. none

100.18

The iron was determined as Fe2O3 , FeO not being tested for.- The 

analysis agrees well with the-formula

H4Al2Si2O9 +H2O.

a Am. Jonr. Sei., vol. 20, 1SSO, p. 283. &Ibid., 32, 1SS6, p. 355.

121
122 CONTRIBUTIONS TO MINEKALOG^. [BULL. 262.

2. AMBT-jYGOjSTITE.

The occurrence of amblygonite at the lepidolite mine at Pala, Cal., 

has already been noticed, and a somewhat fuller description of the 

mineral is here given. A large deposit has been uncovered, and the 

indications seem to show that it is merely a small part of an extensive 

body of massive amblygonite. The mineral usually occurs pure; very 

rarely small amounts of lepidolite are present with it. Frequently 

broad cleavage faces with irregular outlines can be seen. The color 

is white and in thin pieces the mineral is translucent. It fuses easily, 

coloring the flame red, and in powder is difficultly decomposed b}r 

sulphuric acid.

An analysis of a specimen kindly presented by Mr. G. F. Kunz 

gave the writer the following results:

P2O5 ------------------------------------------------------- 48.83

A12O3 ...........:........................................... 33. 70

Fe2 03 ....................................................... .12

MnO ....................................................... .09

MgO .................................................. .....'. .31

Li2O.. ....................................................... 9. 88

Na20 ...........................................:.. ......... .14

H2O........................................................ 5.95

F ..-.........-..---..---...-.--..---.......,-...-- .......--. 2. 29

TiOo..-........_..---.-----.-------._--..--..--.---...--.-.. none

101. 31 

Less 0.............'...........-........................-..... .96

100.35

Regarding fluorine and hydroxyl as isomorphous, in the specimen 

analyzed the latter greatly predominates over the fluorine. The water 

was determined by ig-niting the mineral with lead oxide, previously 

heated nearly to fusion. Three determinations gave the loss of weight, 

due to the escape of water, as 5.89, 6.01, 5.95 per cent. The loss of 

the mineral on ignition was 8.03 per cent, equaling the sum of the 

water and fluorine content.

3. BOOTHITE.

A specimen of a pale-blue copper sulphate was collected at the 

copper mine near Canipo Seco, Calaveras County, Cal.,.by Mr. James 

Wise and kindly presented to the writer for investigation. The paleblue color suggested that the mineral might be boothite instead of the 

more frequently occurring chalcanthite. The results of a chemical 

analysis have shown that the mineral is boothite, thus affording a 

second locality for this interesting mineral. Careful quantitative 

determinations of hydrous copper sulphates will probably show that 

the heptahydrate is not so rare as may be supposed.
SCHALLER.] MINERALOGICAL NOTES. 123

 The mineral from Campo Seco occurs massive, showing no crystalline structure. ' The average of several determinations.afforded the 

results shown below.

CnO .................................................

FeO ...............................................

MgO ...............................................

so;i .............................. ...............^...

H2 0(1.10°) .........................................

H.,0 (above 110°) ...................................

20. 13

.81.

.64

27. 25

36. 76)

Ul. 67 

4. 91.J

3.96

100. 46

Ratio.

1 . 00

.03

.05

1.04

6. 22)

[7. 06 

.84)

Formula, CuSOrH2 0+6H2 0.

A careful determination of the specific gravity of the mineral gave 

(21° C.) 1.944. This being much lower than the value obtained (2.1) 

on the boothite from Leona Heights, a redetermination of the latter 

was made on purer material collected since the publication of the first 

results." This gave as an average value the figure (22° C.) 1.935. 

The average of these two determinations, or 1.94, is probably very 

near the true value foi\the specific gravity of boothite.

4. PISANITE.

A small specimen of massive pisanite from Gonzales, Monterey 

County, Cal., was analyzed some time ago and the results are here 

presented. The quantit}' of material available for analysis was very 

small and the determinations do not claim any great accuracy. About 

6 per cent of insoluble matter has been deducted and the results recalculated to.100 per cent.

CuO........................ '............................

FeO ....................................................

RO

H a 0 ....................................................

7.56

15.85

30. 74

.45. 85

100. 00

Ratio.

Q.27\

k). 89 

.72)

1.08

7.18

The analysis approximates to the formula CuO.2Fe0.3SO3 .2lH2 0.

"Schaller, W. T., Minerals from Leona Heights, Alameda County, Cal.: Bull. Dept. Geol. Univ. 

Cal., vol. 3, No. 7.
124 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

In the following table all available-analyses'of pisanite are tabulated, and one can readily see that there is no definite ratio' between 

the copper and.iron. The formula is then written (Cu,Fe)S04 .7H2 0, 

pisanite being an isomorphous mixture of melanterite and boothite. 

All the analyses are calculated to 100 per cent."

CuO ........................

FeO

so,. ........ l.....;.-.. ......

H,O ...:....................

CuO.........................

FeO. ........................

S03 .........................

H,0. ........................

No. 1.

25. 86

28.80 

45. 34

100. 00

No. 2. .

7.56

15.85 

30. 74 

45.85

100. 00 .

No. 7.

15. 56 

10. 98 

29. 90 

43.56

100. 00

No. 3.

9.17 

16. 37 

29.00 

45.46

100. 00

No. 8.

17.45 

10. 18 

28.43 

 43.94

100. 00

No. 4.

10.07 

(16. 15) 

28.84 

(44..94)

100. 00

No. 9.

17.64 

9.62 

28.27 

44.47

100. 00

No. 5.

12. 61 

14. 14 

28.44 

44.81

100. 00

No. 10.

18.81 

8.51 

27.93 

44. 75

100. 00

No. f>.

 15. 52 

12. 14

27.82 

44. 52

100. 00

NO. n.

27.85

28.02 

44. 13

100. 00

5. GYKOZITE.

In the same rock and but about 50 feet distant from the place where 

the pectolite 6 and datolite occur, at Fort Point, San Francisco, Cal., 

were a number of veins of a pearly massive zeolite, which analysis 

showed to be gyrolite. The veins, ranging from microscopic size to a 

thickness of nearly a centimeter, occur in a dark "basic igneous rock, 

probably a basalt. The gyrolite has replaced the rock and grown outward from both sides of the vein, forming a contact line in the middle 

where the two parts join. The mineral is grouped in spherical and 

also in massive platy or plumose aggregates. It is at times associated 

with apoplryllite, but usually occurs pure. Its color on the-fresh 

fracture is white, while on the weathered surface it is a brownishyellow. It has a decided pearly luster and possesses a good cleavage.

Under- the microscope, a thin section of the rock containing these 

veins sho\vs that the rock has been replaced by this secondary mineral, 

always commencing as a minute vein, probably originating in a micro-

« Anal. No. 1, theoretical couip. of melanterite. FeSO4.7H»O. No. 2, Schaller, anal, quoted above; No. 

3, Schaller, Bull. Dept. Geol. Univ. of Cal., vol. 3, No. 7; No. 4, Hintz, Zeit. Krys., 2, 309; -No. 5, Hillebrand, Bull. U. S. Geol. Survey No. 220, p. 105; No. C, see No. 3; No. 7, Pisani, Comptes Rendus, 1859, 

48, 807; No. 8, see No. 3; Nos. .9 and 10, Hern, Zeit. Krys., 26, 16; No. .11, theoretical comp. of boothite, 

CuSO4 .7H2 0.

Z>Eakle, A. S., Mineralogical notes: Bull. Dept. Geol. Uuiv. Cal., vol. 2, No. 10, 1901.
SCHALLER.] MINERALOGICAL NOTES. 125

scopic fissure of the rock. A multitude of these veins are present, 

lying in nearly parallel position and varying greatly in size. There is 

"nothing to suggest that the gyrolite may have been derived from 

apophyllite. It may have been derived entirely from the igneous 

rock or only in part. The mineral was first deposited at the walls of 

the vein and from thence grew outward into the open fissure from 

both sides, also probably replacing the rock wall. The thin section, 

as well as the hand specimen, shows a decided plumose structure of 

the mineral. These plumose aggregates show, under crossed nicols, 

the black extinction cross. The interference, colors are bright and 

vivid. lieddle" says of these: "The sections of orbicular gyrolite 

are among the most splendid of polariscopic objects, resembling a circularly opened fan, of most brilliant and abruptly contrasted colors."

The properties of the mineral are not very well known. Hedclle 6 

mentions some crystals resembling heulandite in form.' The mineral 

is described as unaxial, though as a matter of fact it is biaxial, but 

like biotite the axial angle becomes 0° at times. Cleavage plates 

show the emergence of a bisectrix. The (approximate) measurement 

of 2 ENR gave values (on the Fort Point material) of from 0° to 25°. 

The sign is always negative. Heddle obtained 2 E = 0° 3°. When 

there was a straight edge suggesting a possible crystal direction, the 

extinction was not parallel.

Dana 6' gives as the formula of the mineral 3H2 0, 2CaO, 3Si.02 , 

while Clarke rf gives 5H2 0, 4CaO, 6Si02 , which is the formula deduced 

by the writer from the following analysis of the San Francisco 

mineral:

Si02 ...-. ..........:.....................................

A1A ------------------------------------------------------

CaO........................................... ............

Na,o ...............................:.........;.........:.

H,0................ .................... :.....,...........

. 53. 47

' .22

32. 00,

1.25

13. 21

1(XX 15

Ratio.

6.02

| 4.02

4.99

The specific gravity is 2.39. Traces of iron, magnesium, and 

potassium are present, while strontium, chlorine, and fluorine are 

absent.

« Hecldle, M. F.', On the optic properties of gyrolite: Min. Mag., vol. 9, 1890-1891, p. 391. 

''Heddle, M. F., On the crystalline form of gyrolite: Min. Mag., vol. 8,1888-1889, p. 272. 

^ o System of Mineralogy, Cth'edition, p. 506, 1892.

rfClarke, F. W., The constitution of the silicates: Bull, U. g. Geol. Survey No. 125, 1895, p. 81,
126 CONTEIBUTIONS TO MINEKALOGY, [BULL. 262.

The mineral is easily decomposed by hydrochloric acid. Certain analogies can be noted between heulandite and gyrolite, and from this and 

the properties of the mineral, as far as known, the writer believes 

gyrolite to be monoclinic. Heddle says in connection with some plane 

angles he measured on gyrolite from Scotland: "The above, as far as 

it goes, seems to show gyrolite to be oblique, and near heulaudite in 

form." 

The formulas of the two minerals are also similar.

Gyrolite.................................. 6Si02 . 4CaO. 5H,0.

Heulandite............................... 6Si02 . A12 03 - CaO. 5HaO.

6. APOPHYI^LITE.

With the gyrolite were found a number of specimens of clear, transparent, but very minute crystals of apophj'llite. These are usually 

less than 1 mm. thick and show only the base, prism of the second 

order, and the unit pyramid of the first order. Some years ago a 

specimen - was obtained here on which the apophyllite crystals have 

been changed to quartz. As they proved to be infusible, a more 

extended investigation of them was made.

The crystals, from 1 to 3 mm. in diameter, appear cubic, with the 

corners truncated.by small faces. Measurements of the best crystals 

showed that they are tetragonal and that they agree in angles with 

those of apophyllite. The prism faces are vertically striated and faces 

of the other two forms are also rareljr somewhat striated.

By trial it was found that hydrochloric acid does not attack the 

crystals, so that the associated calcite was easily removed and pure 

material for analysis was obtained. The crystals are opaque, arid no 

optical determinations could be 'made.

The analysis gave the following figures, showing that the crystals 

are now, chemically, essentially silica with various impurities:

Si02 ......................................................... 90.58

A12 03 ....................................................... 1. 58

CaO ....................................................^... 1. 87

MgO ....................................................... 2.20

H,0 ........................................................ 4.32

100. 55 

7. TEUDURITE.

Several small crystals of tellurite were referred to the writer by 

Doctor Hillebrand. Their locality is the W. P. H. mine, Cripple 

Creek, Colo. The crystals are transparent yellow and reach a length 

of about 2 mm. They are^thin tabular parallel to the brachypinacoid. 

This form is normal to a bisectrix, and the axial plane is parallel 

to a (100).
SCHAI.LER.] MINERALOGICAL NOTES. 127

The crystals show numerous vicinal faces, which are here not given. 

The forms which were established are*

. J={010}, r={l20}, *A= 

The angles measured are:

/>-010 --........-.....-.....---..-.-.

1 120 ...............................

/t-520 ...............................

/ 210

]> l'\'\

Measured.

* 

o /

6 oo

47 34 

 79 30 

77 17 

65 47

p0 /

90 00 

90 00 

90 00 

90 00 

48 14

Calculated.

* 

o /

0 .00 

47 30 

79 37 

77 06 

65 23

po /

90 00 

90 00 

90 00 

90 00 

48 16

The two new forms, h and I, gave the following measurements:

fc={520}.

Crystal No. 1 .........................

DO ......................:.......

Crystal No. 4. ........................

Do ..............................

Do ..............................

Measured, 

<?>.

0 /

79 01

79 ' 19

79 14

80 59

79 02

79 26

Calculated, 

<#>.

o /

sf*

 79 37

On crystals Nos.l and 4 the faces are very narrow, while on crystal No. 2 they are much broader. 

The reflections were fairly good.

Z={210}.

Crystal No. 3 .........................

Do ................... J ..........

Measured,

0 /

77 21 

77 12

Calculated,

}

0 /

77 06

FIG. 9. Tellurite.

The faces were both narrow and the reflections were rather poor.

It seems to the writer that the axial ratio as given by Dana should 

be preferred to that of Goldschmidt, who doubles both the a and c 

axes. This would make the (only) terminal form the unit pyramid,

"Dana's letters and indices.
128 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

while the forms in the prism zone have as simple indices in one case 

as in another, as can be seen from the following table.

b. ....................

m ....................

s .....................

Dana.

010

110

120

140

Goldschmidt.

010

210

110

120

h.... ................

I ....................

p ....................

Dana.

520

210

111

Goldschmidt.

5.10

410

212

S. PBEHNITB.

A mineral from Lower California, sent by G. F. Kunz for determination, proved to be prehnite. The anatysis gave the following 

results: .

SiO,.................................................. T ....... 43. 48

Al-A- ..................................................... 24.52

Fea03 ...-.......-.--......-...----..-.--...-....-----:...-..-. .34

CaO...............'........................................... 27.19

H,0...........................'...............'................ 4. 49

Specific gravity

100.02

2.90

9. HORNBLENDE.

Coating the walls and projecting into the amygdaloidal cavities of a 

lava from Mono County, CaL, were noted small crystals of hornblende, 

tridymite, and biotite. The locality of the rock, which was kindly 

furnished-by Mr. Maynard Bixby, of Salt Lake Cit}^ is given as 8 

miles west of Bridgeport, Mono County, Cal. The hornblende and 

tridymite occur in sharp crystals, of which a few were measured.

Biotite occurs abundantly as small hexagonal plates, Avhich, under the 

microscope, show at times a zonal banding in color, the darker being 

on the outside. The axial angle is very small at times uniaxial.

The hornblende occurs as long prismatic ciystals, becoming extremely 

acicular and hairlike at times. It is often grouped in radiating bunches 

and again occurs in single prisms. Their maximum thickness is about 

one-half millimeter, and in length they reach not over 5 mm. Under 

the microscope the pleochroism is in shades of brown. The maximum 

extinction was 15°.
SCHALLEK.] MINEEALOGICAL HOTES. 129

Two terminated crystals of measurable size showed the following 

forms: c={00l}, &={010}, a={100}, w={llO}, £={20l}, s-{02l}, 

£={131}. . .

c = 001 ..............................

6 = 010 ..................... ...... .

o = 100 .................. ..'..........

m= 110 ..................... .....

t = 201 ..................... .....

z = 021 ...............................

i = m.... .......................

Measured.

*.

o /

90 25 

0 00 

90 14 

62 08 

90 03 

24 32 

18 18

p0 /

14 57 

90 00 

90 00 

90 00 

40 36 

.32 50 

42 45

Calculated.

<*>.

0 /

90 00 

. 0 00 

90 00 

62 05 

90 00 

24 28 

18 03

p0 /

14 58 

90 00 

90 00 

90 00 

40 05 

32 50 

42 49

Crystal No. 1 shows: a,, b, c, m, t, z, i. 

Crystal No. 2 shows: a, b, , m, , z .

10. TRIDYMITE.

Small hexagonal plates of tridymite, 1 mm. in diameter and rarely 

larger, are rather plentiful in places. The forms present on two 

crystals which were partially measured are c={000l}, m={l010}, 

£={3250}, £={5490}, r={3034{,'/=}l012}. The first crystal measured 

was a twin.

c^m .....................................................

m^i.. .................................... ................

C )»

CsJ... ....................................................

Measured.

0 /

35 06

90 02

23 20

26 39

54 48

43 54

Calculated.

0 /

35 18

90 00

23 25

26 20

55 03

43 39

11. ZINNWAiLDlTE.

The occurrence of this lithia mica has already been mentioned by 

Collier," who has very kindly furnished the writer the numerous samples collected. He gives as the exact locality: On Cassiterite Creek 

(extension or branch of Lost River), 5 miles from the coast and 8 miles

a Collier, A. J., The tin deposits of the York region, Alaska: Bull. U. S. Geol. Survey No. 229, p. 20.

Bull. 262 05 9
130 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

east of Cape York, Alaska. It is stated to occur in a vein cutting 

through limestone. The bowlders showing the zinnwaldite are float, 

and in some of these there is a vein, about a centimeter thick, consisting almost entirely of zinnwaldite. Others show the zinnwaldite 

scattered through massive quartz. Cassiterite is associated with 

both modes of occurrence. As further associations Collier mentions 

fl.uar.ite, feldspar, calcite, tourmaline, topaz, pyrite, garnet, galena, 

wolframite, and malachite.

The zinnwaldite has a brown color, and occurs massive without any 

crystal boundaries. It fuses easity to a black mass, coloring the flame 

crimson. An incomplete quantitative analysis showed that the mineral is undoubtedly zinnwaldite. The small dikes before mentioned 

are bordered on one side by a rim Of blackish green mica. This rim 

is about 1 mm. wide and is well developed only on one side of the 

dike, though it is present on the other side in smaller amount. Under 

the microscope the rim has a green and brown color and is uniaxial 

nearest the limestone, but the axial angle increases as the zinnwaldite is approached. In many places the two micas are intergrown. 

The difference in color from the green to the almost colorless zinnwaldite is very marked. The green mica is probably biotite, possibly 

somewhat altered to chlorite. Further description of the zinnwaldite 

is deferred for a later paper. Of the associated minerals, cassiterite 

and topaz occur in small crystals, a brief description of which follows. 

The association of cassiterite, topaz, and zinnwaldite is also noteworthy.

12. CASSITERITE.

The crystals of cassiterite vary in size, ranging from a thickness of 

less than 1 mm. to several cm. The large ones are opaque and black; 

the smaller ones are usually transparent and light brown in color, 

becoming nearty colorless at times. Twins are very common.

The large crystals usually show the simple combination of &={100}, 

w={llO}, e={Oil}, s={lll}, while the smaller ones usually are more 

complex. Two such small ones were measured, the first one a simple 

crystal, the second a twin. The forms noted are: #={100}, m={llO}, 

£={340}, 7?={570}1, r={230}, A={120}, *={01l}, s={lll},/={23l}, and 

the new prism Z=
SCHAU.KR.] MINEKALOGICAL NOTES.

The following are the measured angles:

131

a=100 ..............................

m=110 ...............:..............

&-340 ..............................

#-570 ..............................

r-=230 ..............................

ft-120 ......... .......... t..........

Z-140 ..............................

e-011 ..............................

8=111 ..............................

/-231 ...............................

Measured.

</> 

' o

0 

45 

36 

35 

33 

26 

13 

0 

45 

33

/

00 

00 

35 

48 

37 

30 

56 

03 

01 

46

po

90 

90 

90 

90 

90 

90 

90 

33 

43 

67

/ 

00 

00 

00 

00 

00 

00 

00 

48 

35 

39

Calculated.

* 

o

0 

45 

36 

35 

33 

26 

14 

0 

45 

33

/ 

00 

00 

52 

32 

41 

34 

02 

00 

00 

41

po

90 

90 

90 

90 

90 

90 

90 

33 

43 

67

/ 

00 

00 

00 

00 

00 

00 

00 

54 

33 

35

The prism £={140} was noted three times as a narrow face, measurements of which gave the following values for the </> angle:

o / 

13 49 

13 19 

- 14 40

The dominant terminal form is {ill}, though {Oil} becomes at times 

fairly large. {231} occurs on crystal No. 1 as minute faces and also as

long, narrow line faces.

13. TOPAZ.

Two small crystals, about 2 mm. long, which were measured, showed 

the following forms:« £={010}, m={llO}, Z={l20}, tf={250}, ?={130}, 

y={02l}, /={011}, w={!12}, *={335}j 0={lll}. The crystals were 

rounded and broken and gave, on the whole, rather poor signals. The 

measurements serve, however, to determine the forms.

6-010 ..............................

m-110 ..............................

Z-120 ..............................

7T-250 ..............................

y-130 ..............................

y-021 ..............................

/ -on ..............................

it-112 ..............................

s-335 ..............................

o-lll ..............................

Measured.

* 

0

1

61 

43 

37 

32 

0 

0 

61 

61 

63

/ 

36 

59 

28 

00 

26 

38 

38 

56 

42 

10

po

90 

90 

90 

90 

90 

 61 

44 

45 

50 

63

/ 

00 

00 

00 

00 

00 

44 

24 

39 

31 

00

Calculated.

*.

o

0 

62 

43 

37 

32 

0 

0 

62 

' 62 

62

/ 

00 

08 

25 

07 

14 

00 

00 

08 

08 

08

po

90 

90 

90 

90 

90 

62 

43 

45 

50 

63

/ 

00 

00 

00 

00 

00 

20 

39 

35 

46 

54

The only terminal form on crystal No. 1 is w=

aGoldschmidt's orientation, chosen in Winkeltabellen.
7

132 CONTRIBUTIONS TO MINEKALOGY. [BULL. 262.

14. BOURNONITE.

An analysis of massive bournonite from Bogg's mine, Big Bug district, Yavapai County, Ariz., furnished for analysis by Prof. C. 

Palache, yielded the figures given below.

. 'S. ......................................................... 20.04

As ............:............................................. 2.81

 Sb .......................................................... 118.99

.\Pb ............ ................................................. 40.21

Cu ............................................................ 15.12

Fe ...............,........................:...-...........'.... .35

Zu..............................:........................... .35

Mn.......................................................... trace

Insoluble.................................................... 1.67

99. 54 

15. ANHYDRITE.

A deposit of crystallized anhydrite occurs in Texas, the exact locality 

of which is not known. The crystals are small, reaching a maximum 

of 1 mm. in length, and are tabular parallel to the niacropinacoid.

The base is present as a long, narrow face. 

The clinopinacoid is probably present, but 

the zone of brachydomes is very rounded 

and striated, no sharp faces occurring in 

this zone. Under the microscope the crystals show that the axial plane is parallel to FIG. 10. Anhydrite. i < \

and the acute bisectrix is normal

to #={lOO}. The interference figure is about as large as that of muscovite and is positive. An analysis was made of the mineral, to leave 

no doubt as to its identity.

CaO ...................:.................................'... 41. 01

SO, ..........................'.....;........-................. 58. 87

Ign .............I..... .' . ................................... .22

Insoluble ................................................... .06

100.16 

16. GLAUCODOT.

A sample of cobalt ore from the Standard Consolidated gold mine, 

Sumpter, Oreg., consists of glaucodot, with pyrite and perhaps other 

sulphides, in a dark silicate rock. Imperfect crystals are abundant, 

though they usually show but one or two faces. Much of the ore is 

massive, and it is practically impossible to determine whether it is all 

glaucodot or in part cobaltite. One crystal was measured. The 

small crystal (about 1 mm. long) is orthorhombic, and shows the following forms: w={110},. J={010}, <?={101}, and a very much striated 

brachydome zone in which the following forms are probably present: 

{014}, {013}, {012}.
BCHAU.ER.] MItfERALOGICAL NOTES. 

The following are the angles obtained:

133

/

b =010 ..............................

m=110 ........... ..................

e =101 ..............................

r =014 ..............................

q -013 ..............................

s =012 ..............................

Measured.

</>.

o / 

0 34 

56 10 

90 20 

0 34 

0 34 

0 34

po /

90 00 

90 00 

. 60 22 

15 33 

22 00 

29 00

Calculated.

* .

o /

0 00 

55 34 

90 00 

 0 00 

0 00 

0 00

po /

90 00 

90 00 

60 04 

16 34 

21 39 

30 46

Many other signals between these were seen in the striated brachy-. 

dome zone, but they probably belong to no definite face. 

The analysis gave the following results:

As.. ......................................................

S.... :.........:..............:...........................

Fe. .......................................................

Co........................................................

39.84

18.46

12.45

20.23

9.38

100. 36

Katio.

0.94

1.04

| 1.02

Nickel and antimony were not determined, though thej7 were shown 

not to be present in any quantity. The 

ratio of the cobalt to iron is 31:20 or 3:2, 

so that the formula may be written

instead of

Cos Fea AsB S5 ,

R AsS, R=(Co, Fe). 

17. PYRITE.

A small group of pyrite ciystals from 

Spanish Peaks, Colo., kindly presented to 

the writer by Mr. R. Sargent, showed, on FIG. n.-Giaucodot. 

examination, a rich combination of forms,

especially in the pyritohedral zone. The faces are for the most part 

not striated and give excellent reflections. In size the crystals reach 

a maximum of about one-half centimeter in diameter. They were so 

closely crowded together that only a small portion of each crystal 

was developed; consequently, when the group was broken, a few fragments showed only one or two zones of faces.
134 CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

Twenty-five forms are present on the twelve crystals measured. 

They are:

'c=100 a=470 5=450 q =112

J=1.10.0 h =350 4=560 o =111

b =180 C=580 r=670 u =221

/=140 

a =130 

e =120 

JB=590

.D=570.' 

i =340 

#=790

d =110 

#=114 

m=113

x =123 

^=124 

fij=134

The average of the angles measured with the calculated angles are 

shown in the following table:

No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Letter.

C

A

b

/

a

e

B

a

h

C

D

i

E

d

Y

d

K

m

Q

0

u

X

*

CO

Symbol.

100

1.10.0

180

140

< 130

120

590

470

350

580

570

340

790

450

560

670

110

114

131 '

c 112

I 121

111

( 122 j

\ 221

( 123

132

[ 231

124

134

Measured.

*.

0 /

90 00

5 49

7 08

14 03

19 06

26 34

28 59

29 30

31 04

31 59

35 17

36 52

37 47

38 39

39 48

40 36

45 00

45 00

18 33

26 34

44 59

45 00

45 00

26 34

26 35

18 31

33 42

26 20

18 18

p0 /

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

19 25

72 45

65 54

35 15

54 44

70 31

48 13

36 40

57 40

74 30

28 40

39 37

Calculated.

*.

0 /

90 00

5 43

7 08

14 02

18 26

26 34

29 03

29 45

30 58

32 -00

35 32

36 52

37 52

38 39

39 48

40 36

45 00

45 00

18 26

26 34

45 00

45 00

45 00

26 34

^26 34

18 26

33 41

26 34

18 26

p0 /

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

90 00

19 28

72 27

65 54

35 16

54 44

70 31

48 11

36 42

57 41

74 30

29 12

38 19
SCHALLER.] MINERALOG1CAL NOTES. 135

Qf the p3^ritohedrons i is the dominant form and is always well 

developed in large broad faces, e, #, <?, y occur quite frequently as 

smaller faces, while b, /', a, <*, A, are rarely present as very narrow 

faces, c is also harrow but never striated, always giving perfect 

reflections. The dodecahedron, cZ, is usually somewhat uneven. The 

octahedron, 0, and q, u, and a? occur commonly, while k, m, ?/;, K> were 

observed but once each.

18. VAISTADESTITE.

A specimen of vanadinite, doubtless from Yuma County, Ariz., 

shows, a few crystals that possess a large number of forms. The 

crystals are 3 mm. long and 2 mm. thick, and present the usual 

appearance and habit of vanadinite. The zone c in is, however, very 

rich in forms. A number of vicinal forms were encountered that 

seem characteristic of the particular specimen. Sometimes the crystals are broken, or an apparently simple crystal may be composed of 

several ones not strictly in parallel position. In such cases, each 

zone c m was carefully adjusted by itself and the angles were measured. 

A continuous line of signals was practically never encountered, each 

face being distinct and giving a sharp signal.

The forms observed are quoted below.

Known forms: Known forms Continued. New forms Continued.

c=0001 3=3031 A'=11.0.11.3

a=1010 '7T=4041 £=10.0.10.1

&=112p s=1121 Vicinal fonus:

/i=2130 t;=1122 26.0.26.25

,7=3140 £=2131 43.0.43.40

tf=1013 5=4154 19.0.19.10

r=1012 /=3252 15.0.13.7

/ .r=1011 New forms: Doubtful forms:

5=5054 eZ=5380 »i=ll.q.lT.10

7=4043 /;=3034 JS=9095

«=3032 0=7076 7^=9094

/S=50B3 - ?.i=707_5 E=8083_

t/=2021 ^1=7074 G = 10.0.10.3

'(/=5052 . J/=7072 F=11.0.II.4
136 CONTRIBUTIONS TO MINERALOGY. [BULL. 262. 

The measured and calculated angles for all these forms are:

No.

1

2

3

4

5 t

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

Letter.

C

a

b

h

(J

d

6

r .

k

X

n

0

d

Y

u

a

ft

A

B

y

D

7

E -

.F

C

G

H

K

7T

L

s

V

%

a, .

i

Symbol.

Miller.

0001

10TO

1120

" 2130

3140

5380

1013

1012

3034

1011

26. 0. 26. 25

43. 0. 43. 40

11. 0. 11. 10

7076

5054

4043

7075

3032

5053

7074

9095

19.0.19.10

2021

15. 0. 15. 7

9094

5052

8083.

11.0.11.4

3031

10. 0. 10. 3

7072

, 11. 0. 11. 3

4041

10. 0. 10. 1

1121

1122

2131

4154

3252

Measured.

<t>.

0 /

0 00

30 00

19 09

13 54

21 34

.0 00

0 00

0 00

0 00

0 00

6 oo

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0. 00

0 00

0 00

0 00

0 00

0 00

30 15

29 54

19 02

10 56

20 38

po /

0 00

90 00

90 00

90 00

90 00

90 00

15 23

22 22

31 44

39 29

40 26

41 29

42 16

43 54

.45 47

47 37

49 05

50 53

54 02

55 13

56 09

57 24'

58 42

60 25

61 42

63 43

65 30

66 10

67 52

69 53

70 57

71 38

73 04

83 09

54 40

35 22

65 11

41 49

60 03

Calculated.

<t>.

0 f

0 00

 30 00

19 06

13 54

21 47

0 00

0 00

0 00

 0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

0 00

.30 00

30 00

19 06

10 53

23 25

p0 /

0 00

90 00

90 00

90 00

90 00

90 00

15 20

22 21

31 40

39 26 .

' 40 32

41 29

42 08

43 49

45 47

47 38

49 01

50' 58

53 53

55 12

55 57

57 23

58 42

60 25

61 37

64 03

65 29

66 09

67 56

69 57

70 50

71 39

73 05

83 04

54 55

35 27

65 19

43 17

60 50
8CHAU.ER.] MINERALOGICAL NOTES. 137

Following1 is a short description of the new forms, the p. angle only 

being given for the pyramids, </> being 0° 00'.

d={53SQ}: Four faces of. this new prism were noted, always as line 

faces.

o / o /

Meas. </>.... 21 20 Calc. 0....21 47 

33 

37 

48

7tf=3034: Only two faces of this form are present, both on the 

same crystal. The faces, though narrow, are broader than many of 

the others, and gave fairly good reflections.

Meas.... 31 45 Calc.... 31 ' 40 

43

{26.0.26.25J: This and the following form are doubtless vicinal to 

{lOll}, though they both occur a number of. times. This one is present on four crystals, and the measurements show the following values:

Meas.... 40 24 Calc.... 40 32 

26 ac. or 

36 

25 

19 

25

{43.0.43.40}: This vicinal form is present on three crystals and 

occurs nine times. The faces are small and the reflections fair.

Meas.... -41. 24 Calc.... -41 29

30 Calc. for {lOil}, 39° 26'.

- 32 .. 

16 

24 

35 

26

 35 

37

>?, {ll.O.ll.lO}: This form occurs on two crystals. The faces are 

narrow and the reflections but fair.

 o / - - o /

Meas.... 42 24 Calc.... 42 08

20 

. .04

The form can be only classed as doubtful.
138 CONTRIBUTIONS TO MINERALOGY. [BULL. 262. 

: Occurring on three crystals, the following angles were

measured:

or of

Meas.... 43 24 Calc.... 43 49

53

44 06 

14

w={7075}: The reflections from the very narrow faces of this form 

were poor.

O / Of

Meas.... 49 17 Gale.... 49 01

16 

48 42

J.={7074}: This is the most prominent of the new forms, and occurs 

ten times as (relatively) broad faces on four crystals. The reflections 

were usually fairly good.

o / of

Meas...'. 54 52 Calc.... 55 12 

49 

52 

48' 

55 35 

11 

38 

12 

24 

17

.#={9095}: A very doubtful form, present as verj^ narrow faces 

giving poor reflections.

Of Of

Meas.... 56 18 Calc..-.. 55 57 

05

{19.0.19.10}: Another vicinal form, doubtless vicinal to {2021 j.

Of Of

Meas.... 56 59 Calc.... 57 23 

57 18 .

18 Calc. for {2021}, 58° 42'

30

19

C= {15. 0.1 5. 7}: Another vicinal form occurring on three crystals.

Of Of

Meas.... 60 13 Calc.... 60 25 

38 

24

_Z>=:{9004}: A doubtful form present on one crystal.

Of .Of

Meas..,. 61 53 Calc.... 61 37 

30
SCHALUER.] MIJ^ERALOGIOAL NOTES. 139 

^={8083}: A very doubtful form.

o / or

Meas..:. 65 30 Gale.... 65 29 

65

^={11.0.11.4}: A doubtful form.

"of of

Meas.... 66 01 Calc.... 66 09 

19

#={10.0.10.3}: A doubtful form.

0 / O ' /

Meas.... 69 '54 Calc.... 69 57

77=17072}: Though occurring but once as a small face, it gave a 

fairly good reflection.

' Of Of.

Meas.... 70 57 Calc.... 70 50 

JT {ll.O.l'i.3}: Two faces of this form were noted.

Of Of

Meas.... 71 41 Calc.... 71 39 

35

L~{10.0.10.1}: Two faces of this form are present on one crystal.

Of Of

Meas..,. 82 56 Calc....-83 04 

83 21

The average value obtained for p0 is 0.8223.

19. GLOBULAR LEPIDOLITE. 1 i

Text-books on mineralogy do not mention the globular form for the 

lithia-mica lepidolite. Such globular forms have long been known for 

muscovite, and in fact are by no means uncommon for that species. 

While studying the literature of lepidolite in general two occasions 

were noted in which globular lepidolite was spoken of.

One was by vom Ratha in describing the lithia deposits of the island 

of Elba. On page 649 he says: " Zuweilen sind die (lepidolite) Blatter 

zu Kugeln gruppirt" at times the (lepidolite) plates are grouped in 

spheres (^globular).

The second mention was found in Hamlin's b book on Mount Mica, 

Paris, Me., in which he says:

On November 20, 1822, E. L. Hamlin sent to Professor Silliman, at Yale College, 

a box of minerals from the locality, with letters and catalogue as follows: * * *. 

In the catalogue Mr. Hamlin mentions lilac-colored mica as found in small globular 

concretions.

A large specimen of the pegmatite rock in front of Mr. Bowker's 

barn, at Mount Mica, shows a number of these spheres of lepidolite,

« Vom Hath, G., Die Insel BHbu: Zeitschr. cl. d. geol. Qe^., vol. 22,1870, p. 649. 

b Hamlin, A. C., The History of Mount Mica, pp. 16-17.
140 CONTRIBUTIONS TO MINERALOGY. [BULL. 2G2.

several centimeters in diameter. At Auburn, Me. , several specimens of 

globular lepidolite were found in the summer of 1904 by Mr. Wade, 

working on Pulcifer's ledge on Mount Apatite. Some of these were 

fairly large, one such specimen (by no means the largest) collected by 

the writer being 6 cm. in diameter and 2i cm. thick. Here, at Mount 

Apatite, this globular form of lepidolite is abundant and forms one of 

its characteristic phases. It often has a whitish border (a few millimeters thick) of some undetermined mineral (probably a mica) surrounding it.

* 20. MBETHENITE.

Some minute crystals of libethenite, about a millimeter in diameter, 

from Yerington, Lyon County, Nev., proved to be well adapted for 

measurement. As the symmetry of the mineral has been regarded as 

orthorhombic by some writers and monoclinic by others, it was hoped 

that the measurement of these crystals might contribute something to 

the question. The results have been very satisfactory and show that 

the crystals measured are orthorhombic and not monoclinic.

The crystals were collected by Mr. D. Smith, to whom the writer is 

under obligations for the material investigated. Qualitative chemical 

tests showed the presence of copper, phosphoric acid, and water.

Some time after these measurements were made an article by Melczer a appeared on the symmetry and form of libethenite, in which he 

came to the same conclusion as the writer in regard to the symmetry 

of the mineral, his conclusion being based on a large number of measurements of Cornwall crystals. There can therefore hardly be any 

more question as to the orthorhombic character of libethenite.

The crystals measured are minute, less than a millimeter in diameter, but well formed, and the faces usually give veiy good and sharp 

signals. As the unit prism is present on all crystals, they were easily 

adjusted in true polar position and could be quickly and accurately 

measured with the two-circle goniometer.

Under the microscope the crystals always extinguish parallel to the 

.crystallographic axes. No phenomena, such as twinning structure or 

twinning lamellae, could be observed, either under the microscope or 

on the goniometer.

Seven of the most perfect crystals were removed from the matrix 

and measured. The forms observed are: J={010}, w,={llO}, *A={540}, 

.#={310}, *2={410}, e={01l}, d={lOl], {5=

aMelczer, G., Ueber Libethenite: Zeit. f. Kryst., vol. 39, 1904, p. 288.
SCHALLER.] MIKERALOGICAL NOTES. . 141

The angles measured and calculated" for the eight forms given are:

No.'

1

2

3

4

5

6

7

8

Letter.

b

m

h

S

I

e

d

s

Symbol.

Miller.

010

110

540

310

410

Oil

101

111

Measured.

* 

0 /

0 01

46 11

52 26

71 46

77 02

0 00

89 56

'.46 11

p0 /

90 00

90 00

90 00

90 00

90 00

35 03

36 11

45 22

Calculated.

 #> 

o /

0 00

46 10

52 28

72 15

76 30

0 00

90 00

46 10

P"

o /

90 00

90 00

90 00

90 00

90 00

35 04

36 10

45 23

Besides these the prism t = {210} seems to be present on one crystal, though the reflection was very poor and the measured angle 

varies several degrees from the calculated 

value.

Measured (0), 61° 55', calculated (#), 

64° 21'.

The new prism h={540} occurs but 

once, giving a fair reflection.

The new prism i5={410} occurs five 

times, once as a broad face and the other 

times as a narrow face.

Goldschmidt does not give the form 

$={101} in his Winkeltabellen, but Melc-r 

zer gives the form as present on his

crystals, and it also occurs as long, narrow faces on the crystals measured b}^ the writer.

In habit the crystals differ somewhat from that shown in Dana's system, inasmuch as on the Nevada crystals the pyramid s is large, equal 

in size to the brachydome, thus making the prism faces subordinate in 

size. The general appearance of these crystals is shown in fig. 12.

FIG. 12. Libethenitc.

i Calculated angles taken from Winkeltabellen.
142 CONTRIBUTIONS TO MINERALOGY. [BULL.262.

The combinations observed are shown in the following table:

/ 

Crystal 

No.

1

2

3

. 4

5

6

7

 

b

b

b

b

b

b

b

m h

m 

m 

m 

m 

m 

m 

m h

s I e

 _ g

 e.

8 I Je

 e

 I e

 e-

- I e.

d

_

d

d

d

 t

s

s

s

s

s

s

s

s

From all the good measurements, 27 values for p0 and 24 values for 

q0 were calculated, the average values being

p0 =.7308 

q0 =.7014,

which agree very closely with those given by Goldschmidt, namely:

p0 =.7311 

q0 =.7019.

The values obtained for p0 and q0 are as follows:

Pol'

Values.

i i . 729^

. 729'?

. 7301 .

. 7302

.7303

.7304

.7305

. 736k

. 7309

. 7312

.7314

.7316

.7319

.7321

Av., .7308

Measurements.

2

2

1

1

3

3

1

1

1

3

2

3

2

2

27

0,.

Values.

.6993

.7002

.7004

.7005

.7010

.7011

.7014

.7016

.7018

.7021

.7022

.7026

.7028

.7034

Av., .7014

Measurements.

2

3

2

1

1

3

1

1

2

1 .

2

2

2

1

24
SCHAI.LER.l MINERALOGICAL NOTES. 143

The difference in the <f> and p angles, for the forms, calculated from 

the two values, differ not more than a minute. 

The average value obtained by Melczer is

p0 =.7309 

q0 =.7027.

Taking the average of all three sets of values, we have

PoAv

.7308 '

.7311

.7309

, .7309

Qo-

.7014

.7019

.7027

Av., .7020

The axial ratio for libethenite then becomes 

I a: b:c=.9605:1:.7020.

21. CRYSTALLOGRAPHY OF LEPIDOUTE.

A group of lepidolite crystals was collected by the writer in the 

summer of '1904 at a gem mine about 4 miles east of Ramona, on the 

stage road ifrom Ramona to Julian, San Diego County, Cal. The 

mine was opened and worked for its gems, such as topaz, tourmaline, 

garnet, etc. With these are associated quartz, orthoclase in good 

crystals at times several feet long, muscovite', and,"rarely, lepidolite. 

The minerals in question all occur in the loose dirt, filling "pockets" 

in a pegmatite dike.

The specimen of lepidolite under consideration consists of a group 

of intergrown crystals which often reach large size. The group itself 

is about 5 cm. thick and the individual crystals measure about 1 cm. 

across the base, though crystals with a diarheter of 2 cm. are not rare. 

The crystals are also proportionally thick, the average being from 2 to 

4 mm., though a few are somewhat thicker. They are transparent 

and of a very pale pink color, and, in the direction normal to the vertical axis and parallel to the base, of a slightly deeper tint. , They fuse 

easily to a white enamel, coloring the flame an-intense crimson. The 

side faces are usually plane, not rounded nor striated, and of a brilliant 

polish, giving excellent signals. It is, however, extremely difficult to 

secure a complete crystal from the group owing to the perfect basal 

cleavage, which will cause a crystal to split into a number of layers. 

This will also at times cause part of a crystal to become slightly displaced. In consequence of this difficulty most of the crystals measured are only parts of the original crystals, and two such pieces
144 ' CONTRIBUTIONS TO MINERALOGY. [BULL. 262.

measured as separate crystals may, in reality, be parts of one and the 

same crystal.

As may be expected, the crystals of lepidolite are similar to those 

of muscovite. They also show, however, some marked differences. 

The interfacial angles are nearly the same and the crystals are naturally referred to the same axes as muscovite. There are three marked 

differences between these crystals and those of muscovite: (1) The 

rarity of twins, only one being found in twenty-one crystals; (2) the 

absence of the characteristic face of muscovite, M = {22l}; and (3) the 

presence of the a face {100}, occurring on 10 out of 21 crystals. The 

crystals are not so striated as the green North Carolina muscovites, 

for instance, and in many cases the faces yielded perfect signals.

The common forms are c = {00l}, 5 = {010}, 0 = {lOO}, e = {023}, 

a = {112}, /* = {111}, and x = {131}. Besides these the following have 

been determined: ^={261}, z ={132}, Z = {130}, and possibty several 

others, as {223}, {221}, {112}; also a number of forms which occur for 

the most part as broad faces, giving good reflections, but having 

anomalous indices, and which need further study.

The most frequent combination is c 1) o u x, after which comes c 5 o 

uxe a. Whenever the angle (001): (010) could be accurately measured 

it was found to be exactly 90° 00' in every case, and the distribution 

of the faces also indicates monoclinic symmetry.

It was noticed that the angle between the same forms varied slightly 

on different crystals. The faces were smooth and highly polished, and 

the angles could easily be measured with an error not greater than 1'. 

It is suggested that this variation is real, and is due to the fact that 

lepidolite is an isomorphous mixture of two end products, and as the 

ratio of these two products varies, the crystallographic and physical 

properties of the mineral also vary. Further study on the possible 

correlation of the various properties of the mineral is under way.

This lepidolite belongs to the "second class" of Tschermak or the 

"brachydiagonal class" of Scharizer i.. e/, the axial plane is parallel 

to the clinopinacpid and not normal to it. The trace of the axial plane 

was always parallel to one arm of the percussion figure.

The above is only, a brief preliminary statement. The detailed crystallography of. the mineral will, soon be published in a paper on the 

mineralogy of this entire h'el'u'of lithium minerals in southern California.

The writer's thanks are due Mr. Dan Mclntosh, jr., of Ramona, the 

owner of the mine.
INDEX.

Page. 

TEgirite..................................... 90

Alaska, minerals from ................... 129-131

Alibegoff, G., cited, on separation of uranium ........................... 24

Alunite..................................... 37-41

Alunite-jarosite group ...................... 32-41

Amblygonite............................... 122

Analcite.................................... 76-79

Andalusitic rock ......................... 105,106

Anhydrite..................................'. 132

Apophyllite................................ 126

Argentina, dumortierite from............. 94,-118

Arizona Central mine ...................... 49-51

Arizona Copper Company .................. 47-53

Auburn, Me.............'................... 139

Austria, dumortierite from................. 93-94

Bcaunan, France........................... 92

Becker, G. F., letter of transmittal......... 5

Benedicks, C., on thaliinite and yttrialite..' 61-63 

Bergen Hill, N. J..................... '85-87,89-90

Bertram], E., on dumortierite..... 91,113,"ll9,120

Big Bug district, Ariz ...................... 132

Blue Mountain district, Utah .............. 11

Bogg's mine, Ariz .......................... 132

Bohemia, dumortierite from ............... 93

Boleo, Mexico.............................. 48

Bon Ton mines, Ariz ....................... 46

Boothite.................................. 122-123

Bournonite..............:.................. 132

Boutwell, J. M., willemitc crystals......... 46

Branchville, Conn ......................... .121

Braun, F., on dumortierite localities....... 95

Brignais, France ........................... 92

Brochantite ................................ 52

Buxton mines, <S. Dak..............;....... 37

Calamine................................... 46

Californitc ................................. 72-74

Campo Seco, Cal ............................ 123

Carnotite..............'..................... 9-31

Cassiterite................................ 129-131

Cassiterite Creek, Alaska................. 129-131

Chabazite .................................. 81-84

Chalcocitc.................................. 45-40

Chaponost, France......................... 91

Chase Creek, Ariz .................... 40-47,53-54

Chromium.................................. 14,21

Chrysocolla................................. 47^18

Church, A. H., cited, on silver phillipsite.. 75 

Clarke, F. W., on gyrolite .................. 125

on pseudo-serpentine................... 09-71

on thomsonite.......................... 73

on vcsuvianite....:..................... 73

prefatory note.......................... 7-8

Bull. 262 05 10

Page.

Clarke, F. W., and Steiger,George, cited... 75 

on californite........................... 72-74

Clifton district, Ariz........................ 45

Clifton-Morenci district, Ariz .............. 42

Clip, Ariz.................................. 95,106

Collier, A. J., on zinmvaldite.....'........ 129-130

Cooks Peak, N. Mex.................. 32,34,35,36

Copper Mountain mine, Ariz............... 52

Copper Prince claim, Colo ........... s ..... 24-29

Copper Queen mine, Ariz................... 52

Copper-pitch ore ........................... 48,49

Cornwall, England, minerals from.... 53,140,141

Coronadite ................................. 42-45

Coromido mine, Ariz .................... 42,48,51

Corundum.................................. 39

Cripple Creek, Colo..................... 55,56,126

Cross, W., on nlunite ....................... 37

Cumenge, E., and Friedel, C., on carnotite. 9,

22-24,28-29 

Curie, M. and Mme., on.carnotite.......... 9,26

Cyanite..................................... 96

Damour, A. A., on dumortierite.... 91,93,113,120

Dana, E. S., cited.............. 51,111,125,127,128

Dehes'a, Cal................................. 96

Detroit mine, Ariz.......................... 48,49

Diller, J. S., on pseudo-serpentine.......... 70

Diller, J. S., and Riggs, R. B., on dumortierite ....:.................... 91,120

Dioptase.................................... 46,47

Duling, J. R ................................ 16

Dumortier, E............................... 91

Dumortierite.............................. 91-120

Eakle, A. S., on pectolite................... 124

Elceolite.................................... 90

Emmonsi te................................. 65-56

Faroe Islands................................ 88-89

Ferric tellurites ............................ 56

Ford, W. E., on dumortierite............... 9.1,

96,102,114,116,117,120 

Fort Point, Cal........................... 125,120

' Foullnn, H. von, cited...................... 24

Frenzel, \. B............................... 12

Friedel, C., and Cumenge, E., on carnotite. 9,

22-24.28-29 

Fulmer, El ton. cited ....................... 69

Garh'eld Gulch, Ariz........................ 46,47

Garnet....................................;. 72,73

Gerhardtite..:.............................. 53,54

Germany,dumortierite from. 91,93,94,112,113,118 

Glauebdot ..............-..................' 132-133

Goldschmidt, V., cited ... 110,111,127,128,141,142 

Gounard, F., on dumortierite ............. 91,113

Grand Manan, N. B ........................ 87-88

145
146 INDEX.

PageGyrolite .................................. 124-125

Hal loysite .................................. 121

Haralin, A. C., cited........................ 139

Harlem, N. Y................................ 94

Headden, W. P., cited...................... 37

Heddle, M. F., cited...................... 125,126

Heighway, A. E., ci ted..................... 72

Hemati te................................... 39

Herz, W., cited ............................. 124

Hcumann, K., cited........................ 75

Hidden, W. E., and Mackintosh, J. B.,

cited...................... 61,62,64-68

Hillebrand, W. F., on carnotite and associated minerals................. 18-31

on chromium stains in sandstone...... 14

on distribution of vanadium ........... 17

on dumortierite ........................ -95

on kyanite.............................. 96

on natrojarosite ........................ 33-34

on pisanite ............................. 124

on plumbojarosite...................... 36

on roscoelite............................ 11

on tellurium minerals.................. 55-57

on yttrialiteandthalenite.............. 61-68

Hillebrand, W. F., and Lindgren, W., on

minerals from Arizona ......... 42-54

Hillebrand, W. F., and Penfield, S. L., on

alunite-jarosite group.......... 32-41

Hillebrand, W. F., and Kansome, F. L., on

carnotite, etc................... 9-31

Hillebrand, W. F., and Schaller, W. T., on

lawsonite....................... 58-60

Hills, R. C., cited........................... '46

Hintz, , cited ........................... 124

Hornblende .............................. 128,129

Hurlbut, E. B., cited ....................... 37-38

Imligan, Austria ........................... 93

Indian Creek, Cal .......................... 72

Jannasch, P., cited......................... 118

Jannetaz, E., cited ......................... _4S

Jarosite..................................... 37^41

Jarosite-alunite group...................... 32-41

Jerome mines, Ariz......................... 54

Jones, H. C., cited.......................... 26

Kips Bay, N. Y ............................. 94

Kirghiz Steppes, Russia .................... 46

Knight, W. C., cited........................ 56

Koenig, G. A., cited........................ 49

Kohlschiitter, V., cited..................... 63

Kunz, G. F., cited.......................... 72

Kyanite .................................... 96

Lacroix, A.; and Michel-Levy, A., cited ... 113 

La Sal Creek, Colo.................... 14,16,25,27

Lawson, A. C., cited........................ 96V

Lawsonite.................................. 58-60

Leona Heights, Cal......................... 123

Lepidolite........... 1............ 139,140,143,144

Leucite..................................... 79

Libethenite ........................... 51,140-143

Linck, G., cited .................. 112,113,114,120

Lindgren, W., and Hillebrand, W. F., on

minerals from Arizona......... 42-54

Litchfield, Me.............................. 90

Longfellow mine, Ariz..................... 48

Lyons, France.............................. 91,92

Pago. 

Mammoth mine, Ariz ...................... 47

Mackintosh, J. B., and Hidden, W. E.,

cited ............ 61,62,64,65,66,67,68

Magnet Cove, Ark.......................... 90

Melanochalcite............................. 49

Melczer, G., cited .................... 140,141,143

Merrill,G. P., cited......................... 21

Mesolite.................................... 8.8-89

Metcalf, Ariz ......................... 47,48,52,53

Michel L6vy, A., and Lacroix, A., cited.... 113

Miers, H. A., cited.......................... 47,53

Modoc Mountain, Ariz ..................... 46

Montezuma mine, Ariz..................... 52

Morenci, Ariz............................ 45-48,62

Morencite.................................. 49-51

Mount Apatite, Me......................... 140

Mount Mica, Me............................ 139

Muscovite ... .". ........................... 103,144

Natroalunite ............................... 38-41

Natrojarosite......................... 32-34,38,40

Natrolite ................................... 86,89

New York, dumortierite from.............. 91,

94, 95,106,108-112,114,118 

North Carolina, muscovite from ........... 144

Norway, dumortierite from ............... 94,112

Norway, Me................................ 121

Oberis, Austria............................. 93

Ostero, Faroe Islands....................... 88,89

Pala, Cal ................................". 121,122

Paris, Me................................... 339

Pectolite.................................... 89,90

Penfield, L. S., on dioptase................. 46,47

on libethenite .............\............ 51

on spangolite........................... 52

Penfield, S. L., and Hillebrand, W. F., on

alunite-jarosite group.......... 32-41

Penfield, S. L., and Pirsson, L. V., on willemite.......................... 46

Penfield, S. L., and Wells, H. L., on gerhardtite ........................ 54

Pirsson, L. V., and Penfield, S. L., on willemite.......................... 46

Pisanite .................................. 123,124

Placerville, Cal............................. 20

Placerville, Colo ......................... 9-14,31

Plumbojarosite............................. 32-41

Porter, J. H., cited ................ 32,34,35,36,41

Poulot, C., cited.......................... 9,10,22

Poulot, "., and Voilleque, cited............ 22

Prehnitc.................................... 128

Pseudo-serpentine .......................... 69-71

Pyrite .................................... 133-135

Quartz rock.................................. 98, 99

Ramona, Cal................................ 143

Ransome, F. L., on lawsonite............... 60

on uranium and vanadium ores........ 10-17

Ransome, F. L., and Hillebrand, W. F., on

carnotite, etc................... 9-31

Red Mountain, Colo.................. 37-38,40,41

Riggs, R. B., cited................. 91,114,118,120

Riverside Park, N. Y ....................... 94

Roc Creek, Colo ................. 9,16,24,25,27,28

Romberg, J., cited.......................... 94

Roscoelite............................] 1-14,17,20

Rosita Hills, Colo ..........:............ 37,38,41
INDEX. 147

Page. 

Sandstone, green........................... 18-21

Sandstone, vanaclifcrons................... '20

San .Francisco, Cal......................... 325

San Miguel Jliver, Colo..................... 9-.14

Schaller, W. T., on dumortierite .......... 91-120

on ferric tellurite....................... 55

mineralogical notes.................. 121-144

Schaller, W. T., and Hillebrand, W. F., on

lawsonite:...................... 58-60

Sclimiedebcrg, Germany................... 93

Schobrowitz, Austria....................... 93

Scolecitc.................................... 87-89

Shannon mine, Ariz..j..................... 46,52

Shedd, S., on pseudo-serpentine............ 69

Sierra Abajo district, Utah ................. 11

Silicates, action of silver and thallous ni-

 trates on........................ 75-90

Sillimanite rocks........................... 97-99

Silver analcite............................... 76,77

Silver chabazite...................... 81,82,83,85

Silver natrolite .......................... 85,86,89

Silver nitrate, action of, on silicates ....... 75-90

Silver scolecite ............................. 87,89

Silver thomsonite..................... 79,80,81,85

Sinbad Valley, Colo ........................ 14

Smith, W. B., cited......................... 46

Soda Springs Valley, Nev .................. 32-34

Spangolitc.................................. 52-53

Spanish Peaks, Colo...................... 133-135

Standard Consolidated mine, Oreg......... 132

Stassfurt, Germany......................... 38

Steiger, G., analysis of pseudo-serpentine .. 69 

on action of silver and thallous nitrates on silicates............... 75-90

Steiger, G.,and Clarke, F. W., on "californitc" ........................... 72-74

Stevens mines, Ariz ........................ 46,47

Sti 1 bite ..................................... 84,85

Sumpter, Oreg............................ 132-133

Sweden, dumortierite from ................ 112

Page. 

Table Mountain, Colo ...................... 76,79

Tellurite.................................. 126-128

Tellurium minerals ............. 55,56,57,126-128

Tera/as mine, Ariz ......................... 47

Tetradymite................................ 57

ThalOnitc................................... 61-68

Thallium andesite.......................... 77,78

Thallium chabazite ..................... 83,84,85

Thallium leucite ........................... 79

Thallium mesolite.......................... 88,89

Thallium natrolite ...................... 86,87,89

Thallous nitrate, action of, on silicates ..... 75-90

Thatcher, 1.1. W., cited...................... 69

Thomsonite ................................ 79-81

Topaz .................................... 129-131

Trader, H. B., cited ........................ 57

Tridymite................................ 128,129

Turner, H.W., cited........................ 32

Tvedestrand, Norway ...................... 94

United States Marble Company, Wash...... 69

Uranium ores............................... 9-31

Vanadiferous minerals.............. 9-31,135-139

Vanadinite............................... 135-139

Vanadium ores...................... 9-31,135-139

Vesuvianite................................ 72,73

VoillequG, ,and Pculot, C., cited....... 22

Vom Rath, cited............................ 139

Wassons Bluff, N. S......................... 81,84

Wells, H. L., and Peufield, S. L., on gerhardtitc ........................ 54

Whale Cove, N. B ...................;...... 87-88

Whitehorn, Colo............................ 57

Whitfield, J. E., cited .................... 114,118

Willemite .................................. 46

W. P. H. mine, Colo ........................ 55,126

Yellow Bird claim, Colo.............. 24-29,30,31

Yellow Boy claim, Colo .............. 24,25,27,28

Yerington, Nev........................... 140-143

Yttrialite................................... 61-68

Zinn waldite.............................. 129-130

0