DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

BULLETIN 509

MINERALOGICAL NOTES

SEKIES 2

BY

WALDEMAR T. SCHALLER

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1912

CONTENTS.

Page.

Introduction............................................................ 7

A study of the rutile group............................................... 9

Introduction........................................................ 9

Characteristics of the rutile group...................................... 9

Primary compounds.................................................. 10

Chief primary compounds........................................ 10

Minor primary compounds.....,................'.................. 12

Isomorphous relations of primary compounds.....:.................... 13

Isomorphous mixtures of essentially two of the primary compounds....... 15

Ferrous columbate and ferrous tantalate............................ 15

Ferrous tantalate and stannyl stannate. ............................ 18

Stannyl stannate and titanyl titanate .............................. 22

Titanyl titanate and ferrous titanate............................... 22

Titanyl titanate and titanyl vanadate............................. 26

Stannyl stannate and ferrous stannate.............................. 27

Isomorphous mixture of more than two of the primary compounds....... 29

Striiverite........................................................ 29

Ilmenorutile..................................................... 33

Arsenical cassiterite.............................................. 36

Conclusion.......................................................... 37

Barbierite, monoclinic soda feldspar........................................ 40

Crystallized turquoise from Virginia. ...................................... 42.

Introduction........................................................ 42

General description................................................... 42

Crystallography...............................'........................ 43

Chemical composition................................................. 44

Summary............................................................ 47

Crystallized variscite from Utah.......................................... 48

Introduction........................................................ 48

Occurrence and gem quality.......................................... 48

General description!.................................................. 50

Optical properties.................................................... 50

Orientation and pleochroism...................................... 50

Refractive indices................................................ 51

Structure of crystals..................................."........... 52

Properties of dehydrated lavender variscite......................... 53

Relation to analogous minerals................................... 55

Crystallography....................................................... 57

Introduction.................................................... 57

Calculation of elements........................................... 58

First orientation.................................................. 60

Second orientation................................................ 61

Third orientation................................................ 62

Twin crystal..................................................... 62

Relation to analogous minerals.................................... 62

3
4 CONTENTS.

Crystallized variscite from Utah Continued. Page.

Chemical composition................................................. 63

General properties............................................... 63

Chemical analysis................................"................. 64

Hinsdalite from Colorado .................................................. 66

Introduction........................................................ 66

Occurrence.......................................................... 66

Description of mineral............................................... 66

Chemical composition.................................................. 67

The alunite-beudantite group............................................. 70

Introduction......................................................... 70

Probable identity of hamlinite with goyazite........................... 70

Utahite and related minerals......................................... 71

Miscellaneous notes................................................... 74

Classification of minerals of the group................................. 75

Some minerals from Beaver County, Utah................................. 77

Introduction........................................................ 77

Beaverite............................................................ 77

Occurrence and association........................................ 77

Physical properties.............................................. 78

Chemical composition..........................'................... 78

Wurtzite...........'.................................................. 79

Occurrence...................... '. ............................... 79

Crystallography................................................... 80

Plumbojarosite....................................................... 80

Occurrence and physical properties................................ 80

Chemical composition............................................. 81

Corkite.............................................................. 82

Occurrence and physical properties................................ 82

Chemical composition................'............................. 82

Ferritungstite from Washington........................................... 83

Notes on minerals from gabbro, of Waimea Canyon, Hawaii.................. 85

Introduction........................................................ 85

Apatite.............................................................. 85

Orthoclase........................................................... 86

Titaniferous augite............................ r ...................... 86

Cuprodescloizite from California.......................................... 88

Mineralogy of the .French phosphorites..................................... 89

Introduction. ......................................:.... : ............ 89

Types of phosphorites. ............................................... 89

Description of minerals................................................ 90

Dahllite.......................................................... 90

Francolite1 ....................................................... 91 

Unknown mineral............................................... 91

Collophanite..................................................... 91

Quercyite........................................................ 92

Summary of properties................................................ 92

Chemical composition.................................................. 94

The probable identity of podolite with dahllite............................. 96

The composition of the phosphorite minerals............................... 98

Introduction........................................................ 98

Dahllite............................................................... 98

Francolite........................................................... 98

Collophanite......................................................... 99

Summary............................................................ 100
CONTENTS. 5

Page.

Natramblygonite from Colorado........................................... 101

Occurrence.......................................................... 101

Association............................................ v.............. 101

Description of mineral............................................... 101

Chemical composition................................................. 102

The properties of mosesite................................................ 104

General description................................................... 104

Chemical properties.................................................. 104

Crystallography....... '. ............................................... 106

Optical properties.................................................... 107

Thaumasite from Beaver County, Utah..................................... 110

Introduction........................................................ 110

Geologic occurrence.................................................. 110

Physical character.................................................... Ill

Chemical composition................................................. 112

Bibliography......................................................... 113

The identity of stelznerite with antlerite................................... 114

ILLUSTRATIONS.

Page.

PLATE I. A, Crystallized turquoise; B, Variscite nodule; C, Variscite crystals. 42

FIGURE 1. Structural formulas for chief primary compounds of the rutile group. 14

2. Turquoise crystal............................................... 44

3. Variscite crystal, showing grouping of small particles. ............ 53

4. Variscite crystal............................................... 58

5. Wurtzite crystal............................................... 80

MINERALOGICAL NOTES, SERIES 2.

By WALDEMAR T. SCHALLER.

INTRODUCTION.

The several papers here assembled represent in part the results of 

mineralogical research work carried out by the author in the chemical laboratory of the United States Geological Survey from January 

1, 1910, to the end of the fiscal year 1910-11 (June 30, 1911). Earlier reports of a similar nature have been published as "Mineralogical notes" (1903-1904), a part of Bulletin 262, and "Mineralogical 

notes, series 1" (1905-1909), in Bulletin 490. In-addition to these 

papers a report on the crystallography of ferberite from Colorado 

was prepared (with Mr. F. L. Hess) for publication in the "Proceedings of the United States National Museum," and a report on the 

gem-tourmaline field of southern California has been nearly finished.

Several of the papers contained herein were originally written in 

conjunction with some of the geologists of the Survey. In these 

papers full credit has been given for their contributions, several of 

which have been somewhat rearranged.

7

A STUDY OF THE RUTILE GROUP. .

INTRODUCTION.

The rutile group, as discussed in this paper, comprises the minerals 

rutile, cassiterite^ mossite, tapiolite, nigrine, iserite, ainalite, ilmenorutile, and striiverite, l all of which occur well crystallized. Recent 

analyses of ilmenorutile and striiverite in papers by Brogger 2 and 

by Prior and Zambonini 3 make it possible to study the entire group 

fairly conclusively.

The separation of titanium, columbium, and tantalum, when 

they are found together in a mineral, is not alone a most difficult 

operation, but one in which accurate results are not yet attainable. 

Interpretation of the analyses of such a group of minerals is therefore difficult because the accuracy of the analytical figures is considerably in doubt. Notwithstanding this primary difficulty, the 

explanation herein offered of the composition of the rutile group 4 

serves to interpret the natural occurrences of these minerals and 

seems free from serious objection.

CHARACTERISTICS OF THE RUTILE GROUP.

The rutile group is well defined and striking. It comprises a 

number of minerals generally considered as well-established species, 

though all but two of them are of rare occurrence. A very striking 

fact is that these minerals are very similar crystallographically; for 

not only do they all crystallize in the tetragonal system with nearly 

the same value for the c axis (c = 0.6), but they possess a further 

peculiarity that at once shows their close geometrical kinship in 

that they form twin crystals (twinning plane {101}), distorted 

in a direction parallel to the intersection of the two unit pyramids 

(111) and (111). This peculiar distortion and twinning gave rise 

to the supposed species, skogbolite and ixiolite, which are, in fact, 

only twinned tapoilite crystals. If, now, it can be shown that 

there is a similar close chemical relationship between these minerals, 

sufficient evidence and material will be provided for a satisfactory 

; study of this group.

! l Several other minerals doubtless belong to this group. Among these are zircon, thorite, and platnerite, but they are not included in the present discussion because the elements zirconium, thorium, and 

lead do not enter, so far as known, into the composition of the minerals here discussed.

2 Brogger, W. C., Die Mineralien der sudnorwegischen Granit-Pegmatitgange. I, Niobate, Tantalate, 

Titanate und Titanonlobate: Videnskabs-Selskabets Skrifter, Math.-Naturw. KL, 1906, no. 6.

; * Prior, G. T. and Zambonini, F.,' On striiverite and its relation to ilmenorutile: Mineralog. Mag., vol. 

15,1908, p. 78.

! < All the analyses quoted in this paper have been taken from the literature. The only experimental 

work done consists of some qualitative tests.

9
10 MINERALOGICAL NOTES SERIES 2.

Isomorphous relationships are strongly indicated by these minerals, 

and have already been suggested by several authors, notably Brogger 

and Prior. 1 The paper of Brogger is exceptionally rich in suggestions, and many hypotheses here advanced are proposed by him, 

though some are merely indicated by him as possibilities, their correctness not being demonstrable. The relations of rutile to tapiolite, 

mossite, and the compound FeTi03 are frequently brought out in 

his work. Particularly to the point is his suggestion at the end of 

the discussion of the relations of ilmenorutile that the occurrence 

of the compound FeTiO3 in ilmenorutile makes it probable that 

the pure compound FeTi03 is possible in the tetragonal modification. 

Brogger's paper should be carefully read for a full discussion of the 

relations of these similar compounds.

In short, I would explain this entire group as consisting either of 

members of an isomorphous family or of mixtures of two or more of 

such members in varying proportions. The existence of several distinct 

primary compounds is recognized and three of them occur in nature 

in a pure state. All the other members of the rutile group can be 

satisfactorily explained as. isomorohous mixtures of two or more 

of these primary compounds.

PRIMARY COMPOUNDS.

. CHIEF PRIMARY COMPOUNDS.

The six most important primary compounds may best be treated 

by themselves as a group, reserving the minor compounds for subseouent discussion. These chief primary compounds are the following:

Occurrence of chief primary compounds.

Composition.

Ferrous tantalate. ...........

Ferrous titanate. . ...........

Titanyl titanate............ .

Formula.

Fe(Cb03 )2 ..........

Fe(Ta03 )2 .........

Fe(TiO )..........

(TiO)(Ti08) .......

(SnO)(Sn03 ) .......

Fe (Sn03) .........

Maximum percentage of occurrence in natural minerals.

39 2

Nearly 100

64.0

Nearly 100

Nearly 100

36.1

Mineral.

Tapiolite.

Rutile. a

Cassiterite. °

a The formulas of rutile and cassiterite are given in the form used by Brogger.

In the following description of the chief primary minerals or 

compounds just named, only such data as have a bearing on. the

i Op. cit. Rammelsberg (Handb. Mineralchemie, 2e Auflage, II, Specieller Theil, 1875, p. 357) states 

that the tin oxide present in the analyses of tantalite (probably tapiolite), is to be considered as FeSn08 

in isomorphous admixture. A similar suggestion is offered for the titanium present, which is to be 

regarded as FeTiOs.
THE RTJTILE GEOUP. 11

possible isomorphous relations of the compounds are included. 

Unless otherwise stated the data are taken from Dana. 1 

. Ferrous columbate. The mineral known as mossite was described 

by Brogger,2 who, on the basis of an analysis which showed columbium and tantalum to be present in molecularly equal quantities, 

felt justified in putting forth a new name. Pure or even approximately pure (tetragonal) iron columbate had not been found in 

nature, but Brogger referred the name "mossite" to such tetragonal 

compounds where the columbate is present in the ratio of 1:1 or 

1 + : 1 of the tantalate. The value of the c axis for the isomorphous 

tapiolite is given by Brogger as 0.65215. Brogger's "mossite," a 

mixture of columbate and tantalate, has c = 0.64379. The value 

of the c axis for the pure ferrous columbate should therefore be 

about 0.6354. Similarly, the density of the purest tapiolite analyzed, 

the "skogbolite," 3 is 7.85. The density of Brogger's "mossite" is

given as 6.45. From these data the density of the pure ferrous 

columbate, Fe(Cb03) 2 , is found to be about 5.05, a figure lower than 

the lowest authentic density (5.26) I could find recorded for columbite, which is for the dimorphous orthorhombic form of iron columbate. Similarly, the density (7.85) for tapolite, Fe(Ta03) 2 , is lower 

than the highest recorded value for tantalite. However, these 

figures are of uncertain value. "Mossite" often forms the peculiar 

distorted twinned crystals, elongated parallel to the intersection 

edge of (lll):(lTl).

Ferrous tantalate or tapiolite. The name tapiolite is here used to 

refer to. the pure iron tantalate, Fe(Ta03) 2 . Like "mossite," this 

mineral often forms distorted twin crystals. The values of the c 

axis and the density, which have been given in the preceding paragraph, are 0.65215 and 7.85, respectively.

Ferrous titanate. The tetragonal ferrous titanate Fe(Ti03) 4 is 

present in large amount in iserite. 5 It is the admixed component 

of ferriferous rutile, or nigrine, and occurs in ilmenorutile and striiverite. Its physical properties are not known, but the c axis of iserite 

is close to 0.64 and the density of ferrous titanate has been calculated to be about 5. ± .25. (See p. 12.) Janovsky 8 describes iserite as 

occurring in tetragonal crystals, similar to rutile, twinned on {101}.

1 Dana, E. S., System of mineralogy, 6 ed., 1892.

2 Brogger, W. C., Uber den Mossit und iiber das Krystallsystem des Tantalit (Skogbolit) aus Finnland: 

Videnskabsselskabets Skrifter. I, Math, naturw. Kl., 1897, No. 7, p. 19.

« Dana, E. S., System of mineralogy, p. 734, analysis No. 7.»

« This is the same compound which, in its trigonal or rhombohedral polymorphous form, exists as the 

mineral ilmenite.

& Described by Janovsky and in Dana's "System of mineralogy," p. 239. Not to be confounded with 

iserine (Dana, op. cit., p. 219), which is referred to ilmenite.

' Janovsky, J. V., Uber Niobit und ein neues Titanat von Isergebirge: Sitzungsb. Akad. Wiss. Wien, 

vol. 80, Math, naturw. Kl. (1), 1880, p. 39.
12 MINBRALOGICAL NOTES SERIES 2.

It is of a brown color, but pellucid and honey-yellow in thin lamellae. 

Dana 1 states with regard to Janovsky's iserite 

Groth (Z. Kryst., V, 400) justly remarks that the mineral is not far from the ferruginous rutile called "nigrine," and that a more exact determination as to form, 

homogeneity, etc., is needed, to prove its independent character. If it is an independent species, the name is an unfortunate one, as tending to confusion with the 

distinct iserin, also called iserite.

Titanyl titanate or rutile. The fourth mineral of this group is 

too well known to require extended description. It is tetragonal, 

c = 0.6442, forms distorted twins like tapiolite, and has a density of 

4.2. The interpretation of the composition of rutile as given by 

Brogger and Prior is as titanyl metatitanate (TiO) (TiO3).

Stannyl stannate or cassiterite. Cassiterite, or stannyl metastannate, 

is also well known. It is tetragonal, c = 0.6723, forms distorted twins, 

and has a density of 6.9.

Ferrous stannate. Ferrous stannate, Fe(Sn03), not known in a 

pure state, is assumed to enter into the composition of some Mexican 

cassiterites to a considerable extent. It is probably present, though 

generally in small amounts, in nearly all cassiterites. Its properties 

are, of course, unknown.

Summary. To better show the relationships of these chief primary 

compounds, their essential data, as given in the previous paragraphs, 

are brought together in the table below:

Properties of chief primary compounds.

Composition.

Ferrous tantalate. .......

Titanyl titanate .........

Formula.

Fe(Cb08 )2 ......

Fe(Ta03 )2 ......

Fe(Ti08 ),......

/TSf^ V /'TiO 'i ilU/ U 1U3^- 

(SnO)(Sn03)...

Fe(Sn08 ).......

Density.

5.05?

7.85?

5. ±. 25

4.2

6.9

Crystallography.

c=0.6354.

Tetragonal, distorted twin,

c=0.6522. 

Tetragonal, twinned, c 0.64. a

Tetragonal, distorted twin,

c=0.6442. 

Tetragonal, distorted twin,

c=0.6723.

a Like rutile. 

MINOR PRIMARY COMPOUNDS.

In addition to these chief primary compounds it is necessary to 

assume the existence of several minor primary compounds in order 

to explain the composition of all the members of the rutile group. 

These have not as yet been found in nature either as pure compounds 

or as present to any great extent in isomorphous mixtures. Consequently their properties are entirely unknown, but their close chemii System of mineralogy, 5th ed., Appendix 3, 1884, p. 105.
THE RUTILE GROUP. 13

cal relationship can be seen by comparison of their formulas with 

those of type compounds such as Fe(Ta03) 2 or (SnO)(Sn03). In the 

following list these minor primary compounds are given the highest 

percentages of their occurrence in any of the minerals herein described, 

as calculated by the methods used in this paper.

Occurrence of minor primary compounds.

Formula.

Zn(As03 ) a ............

Zn(Sn03 ).............

Fe(AsOs)2 . ..........

Mn(Ta03V..........

(SnO)(Ta08 )........

(TiO)(V08) 2 .........

Composition.

Zinc arsenate. ..............................

Manganous tantalate. ........................

Stannyl tantalate; presence doubtful .........

Maximum 

percentage of 

occurrence in 

natural 

minerals.

11.6

8.6

2 8

(See p. 20.)

(See p. 20.)

(See p. 26.)

ISOMORPHOTJS RELATION OF PRIMARY COMPOUNDS.

In this paper I have regarded minerals as isomorphous if they 

possess very similar geometric form and close analogy in chemical 

composition, and if they form mixed crystals resembling in form 

those of the end members.

The first of the above three requirements is very well satisfied by 

this group of chief primary compounds in so far as data concerning 

them are available, as is shown by the summary of the properties of 

the compounds in the table just given. The close agreement of the 

values of the tetragonal c axes and the further evidence of the common occurrence of distorted twins is very suggestive of the close 

geometrical relation between the compounds.

The second requirement, close analogy in chemical composition, 

is not so readily disposed of, chiefly because of the incompleteness of the existing knowledge of the chemistry of such compounds as are under discussion. No difficulty has beei\ met, but it 

must be admitted that some of the propositions advanced are only 

theoretical conceptions, though nothing has been so far brought 

against them and their validity is generally acknowledged.

The acids which are considered as isomorphous are as follows:

Columbic acid, H2(Cb03)2 , forming columbates. 

Tantalic acid, H2(Ta03 )2 , forming tantalates. 

Metatitanic acid, H2(Ti03), forming metatitanatea. 

Metastannic acid, H2(Sn03 ), forming metastannates. 

Metarsenic acid, H2(As03)2 , forming metarsenates. 1

i The relative instability of the metarsenates is probably overcome in the Mexican cassiterites (see p. 36) 

by the "mass action" of the predominant metastannates,
14 MINERALOGICAL NOTES SERIES 2.

Ferrous columbate. Q=C6-0-Fe-0-Cb=0

The isomorphous relation of columbic and tantalic acids is too well 

known to require any further comment. The same relation has been 

proved for several compounds of titanium and tin, as, for example, 

for .salts of the type R'2M"" F6, where M"" represents Ti or Sn. 

Ouvrard1 showed the isomorphous relation of the salts Ti2Na(P04 ) 3 and 

Sn2Na(P04 ) 3 . The relation of tin to columbium and tantalum still 

remains to be proved, but the isomorphous relation of stannates to 

columbates and tantalates has been assumed in explaining the composition of a number of minerals. The relation of metarsenic acid to 

the other acids mentioned above is purely theoretical. Thebases which 

combine with the acids to form the compounds whose admixture produces the minerals of the rutile group are Fe", Zn", Mn",

(TiO)", and (SnO)". The relationship of the titanyl group (TiO)" to the 

stannyl group (SnO)" is similar to that 

of the acids and 'hardly needs further 

comment. It is only necessary to see 

whether Fe" and (TiO)" can be considered isomorphous, but I have not 

been able to find any satisfactory 

evidence on this question. Such a 

relation seems very probable and has 

been assumed by numerous writers, 

but it remains to be proved.

That the isomorphous relationships 

of the bases and acids, as here given, 

are real and do occur in nature can only 

be shown by a consideration of the 

evidence as found in the natural occurrences of these minerals. A series of 

salts in which these isoFerrous titanate.

Ferrous tantalate.

0-Fe-O

OTi< >Ti=0 

0-Fe-O

0=Ti<>Fe

0

Titanyl titanate . . . 0=Ti< !>Ti=0

o

0

Stannyl stannate . . 0=Sn<( )>Sn=O

0

Ferrous stannate . .

o

n^ ^

FIGURE 1.-Structural formulas for chief pri- chemical

mary compounds of the rutile group. _ .. morphous relations can be traced may

have been prepared and described, but I was not able to find any such 

descriptions in the literature. The evidence for a chemical analogy in 

these compounds can not, therefore, be considered definitely proved if the 

natural occurrences, which are, of course, the very ones for which the 

relationships are to be proved, are omitted. The evidence is largely theoretical, but at least no negative evidence has so far been brought to bear. 

The formulas of the chief primary compounds may be expressed 

structurally in a form which at once suggests their very close chemical similarity. 2 These are shown in figure 1, the type structure

1 Compt. Rend., vol. Ill, 1890, p. 178.

2 It must be remembered that no claim is made that these structural formulas actually represent the 

composition of the minerals. They do, however, show that analogies exist in the structure of these compounds, and for this reason they serve a very useful purpose.
THE EUTILE GROUP. 15

being taken from Brogger's paper. In the first formula proposed for 

ferrous titanate the formula is doubled, as in this form the close 

relationship to ferrous columbate and ferrous tantalate is better 

shown.

The third requirement of the isomorphous relation, namely, ability 

to form mixed crystals, can not be demonstrated on artificial preparations, as knowledge of these compounds, produced artificially, is 

very small. The natural occurrences, however, afford plenty of evidence of such isomorphous mixing.

Original occurrences of all the primary minerals and of their various mixtures have been found in quartz-feldspar rocks of the 

pegmatite type. Tapiolite, "mossite," and cassiterite are typically found in pegmatite. Rutile is only rarely found in pegmatite; Brogger 1 states that he has never observed rutile in granitic 

pegmatites of south Norway. However, Watson and Taber, in describing the rutile deposits of Virginia,2 speak of its occurrence in a 

"coarse-granined feldspar-quartz-hornblende rock"- whose textural 

relations " over many parts of the rock mass [are] similar to those of a 

coarse pegmatitic granite." Further, "no evidence has been developed from either the field or the laboratory study for regarding the 

rutile as of secondary or subsequent origin." Rutile is also mentioned as an original constituent of the large pegmatite dike at 

Baringer Hill, Llano County, Tex.3 The minerals here considered 

as forming an isomorphous group have therefore the further common 

bond that they have been found in a similar rock, namely, a quartz- 

.feldspar or granitic pegmatite. Of the minerals here considered as 

simply isomorphous mixtures of the primary compounds, ilmenorutile, 

struverite, and probably ainalite are all found in granitic pegmatites.

ISOMORPHOUS MIXTURES OF ESSENTIALLY TWO 4 OF 

THE PRIMARY COMPOUNDS.

FERROUS COLUMBATE AND FERROUS TANTALATE.

The isomorphous relations of ferrous columbate and ferrous tantalate have already been stated (p. 11). It was, in fact, an isomorphous mixture of these two compounds in approximately the 

proportion 1:1 which Brogger described as "mossite."

The analysis given by Brogger of "mossite" from Moss, Norway, 

is given below.

1 Die Mineralien der sudnorwegischen Granit-Pegmatit-gange. I. Niobate, Tantalate, Titanate, and 

Titaniobate: Videnskabs-Selskabets Skrifter. Math, naturw. Kl., 1906, no. G.

a Watson, T. L., and Taber, Stephen, The Virginia rutile deposits: Bull. U. S. Geol. Survey No. 430, 

1910, pp. 200-213.

3 Hess, F. L., Minerals of the rare-earth metals at Baringer Hill, Llano County, Tex.: Bull. U. S..Geol. 

Survey No. 340,1908, p. 292.

4 A third compound is occasionally present in minute quantity.
16 MINERALOGICAL NOTES SERIES 2. 

Analysis and ratios of'mossite " from Norway.

Cb205 .................. ......................... ........

Ta205 . .................................................

Sn02 . .................................................

FeO... .................................................

Per cent.

}

m 82' 92U2

.18.

16.62

99.72

Ratio.

0.116

.118

.001

.231

The ratios show that this mineral consists of 

0.5 part, or 0.2 per cent, of stannyl stannate (SnO) (Sn03) cassiterite. 

116 parts, or 39.2 per cent, of ferrous columbate, Fe(Cb03 )2 . 

118 parts, or 60.6 per cent, of ferrous tantalate, Fe(Ta03 )2 tapiolite.

Brogger's "mossite" is therefore a columbium-bearing tapiolite 

rather than a distinct species, and it would have been better if the 

name had not been proposed. It is hoped, as Hess and Wells 1 state, 

that the " custom of proposing names for unknown extrapolated 

members of a mineral series will not become general," and therefore 

the name "mossite" should be dropped, as it is believed that the 

material from Moss, Norway, is not entitled to specific distinction from 

tapiolite, being in fact only a columbic tapiolite.

Two analyses by Rammelsberg (Nos. 11 and 12 on p. 734 of 

Dana's System of Mineralogy) of tapiolite, or the so-called ixiolite, 

from Skogbole, Finland, gave the following results:

Analyses of ixiolite from Skogbole.

TaA-..!.... ....... ...................................

Cb,05 ...................................................

FeO" SnO,. .................................................

MnO. ..................................................

Ign.... .................................................

Total. ...........................................

1

63.58

19.24

1.70

9.19

5.97

.23

99.91

2

69.97

«12. 26

2.94

| 14. 83

100. 00

o Including 1 per cent TiOz, according to Dana.

Considering the 14.83 per cent FeO + MnO in the second analysis 

as FeO (justifiable because of the closeness of the molecular weights 

of FeO and MnO) and not considering the presence of titanium, the 

folowing ratios are obtained from the above analyses:

i Hess, F. L., and Wells, R. C., An occurrence of struverite: Am. Jour. Sci., 4th ser.,. vol. 31,1911, p. 432.
THE EUTILE GROUP. 

Ratios of analyses of ixiolite from Skogbole.

17

Tt> O

Sn02 . ...............................................

FeO

MnO..................................................

1

fl 1441 .072/- 216

.011

1981 ' 084J- 212

2

0. 158\ on .

. 046J- ZU4

01 Q

.206

From these ratios the composition of the samples of ixiolite is 

found to be as shown below. 

No. 1 consists of 

72 parts, or 24.3 per cent, of ferrous columbate, Fe(Cb03 )2 . 

144 parts, or 74.0 per cent, of ferrous tantalate, Fe(Ta03)2 tapiolite. 

5.5 parts, or 1.7 per cent, of stannyl stannate (SnO) (Sn03) cassiterite.

No. 2 consists of 

46 parts, or 15.6 per cent, of ferrous columbate, Fe(Cb03 )2 . 

158 parts, or 81.5 per cent, of ferrous tantalate, Fe(Ta03 )2 tapiolite. 

9.5 parts, or 2.9 per cent, of stannyl stannate (SnO) (Sn03 ) cassiterite.

An analysis of tapiolite from Sukula, Finland, by Rammelsberg, 

after the tetragonal character of,the mineral had been established, is 

as follows:

Analysis and ratios of tapiolite from Sukula, Finland.

T^ O

Cb205 . ................................................

Sn02 . .................................................

FeO....................................................

MnO...................................................

Per cent.

73.91

11.22

.48

14.47

.81

100. 89

Ratio.

0 167\ 042 j. 209

.003

.2011 . 

. Oil/' £1£

The ratios show that the composition of this "tapiolite" is as 

follows:

1.5 parts, or 0.4 per cent, of stannyl stannate (SnO) (Sn03) cassiterite. 

42 parts, or 14.1 per cent, of ferrous columbate Fe(Cb03)2 . 

167 parts, or 85.5 per cent, of ferrous tantalate Fe(Ta03)2 tapiolite.

Two analyses of tapiolite from Ouster City, S. Dak., are given by 

Headden.1 They are very similar and are made on like material, 

so that the discussion of one of them will suffice. The results, with 

the ratios calculated therefrom, are here given. The density of this 

material is 7.22.

i Headden, W. P., Mineralogical notes, No, III: Proc. Colorado Sci. Soc., vol. 8,1906, p. 167 

23590° Bull. 509 12 2
18 MINERALOGICAL NOTES SERIES 2. 

Analysis and ratios of tapiolite from South Dakota.

TaaO............................... ......................

Fe6 5

Sn02 ....................................................

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

Per cent.

78.61

4.29

16.85

.07

.31

.11

Trarp

100. 24

Ratio.

0 1781

. 016J- Iy*

.234

The above ratios indicate that this tapiolite is composed of:

16 parts, or 5.6 per cent, of ferrous columbate, Fe(Cb03 ) 2 . 

178 parts, or 94.4 per cent, of ferrous tantalate, Fe(Ta03 )2 tapiolite.

The excess of FeO remaining must be ascribed to impure material 

or to some error in the analysis.

The tapiolite from Topsham, Maine, described by Warren, 1 would 

seem to contain a small amount of ferrous columbate, judging from 

the value of the density 7.67-7.68, that for tapiolite being 7.85.

The summary of the isomorphous mixtures of ferrous columbate 

and ferrous tantalate given below shows readily the variation in the 

proportions in which the two compounds have been found in nature.

Isomorphous mixtures of ferrous columbate and ferrous tantalate.

Described by 

Brogger..............

Do..............

Do..............

Headden.......;....

Locality.

Moss, Norway ....................

Skogbole, Finland (1) .............

Skogbole, Finland (2) .............

Sukula, Finland ..................

Ferrous 

columbate.

Per cent. 

39.2

24.3

15.6

14.1

5.6

Ferrous 

tantalate.

Per cent. 

60.6

74.0

81.5

85.5

94.4

As the maximum percentage of ferrous columbate so far found in 

nature reaches only 39.2 per cent, the objection to considering "rnossite " a well-established species is seen to be valid.

FERROUS TANTALATE AND STANNYL STANNATE (TAPIOLITE

AND CASSITERITE).

An analysis of tapiolite (skogbolite) from Skogbole by A. Nordenskiold gave the following results:

1 Warren, C. H., Mineralogital notes: 4. Crystallized tapiolite from Topsham, Maine: Am. Jour. Sci., 

4th ser., vol. 6,1898, p. 121.
THE EUTILE GROUP. 

Analysis and ratios of tapiolite from Skogbole.

19

TaA... ...............................................

Cb205 - :....................-..........................

Sn02 . .... : ............................................

FeO... ...... ...........................................

MnO...................................................

CuO. I.................................................

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

Per cent.

84.44

1.26

13.41

.96

.14

.15

100. 36

Ratio

0.191

.008

186ll99

. 013 / 

From the ratios, the composition is found to be as follows:

4 parts, or 1.2 per cent, of stannyl stannate (SnO) (Sn03) cassiterite. 

191 parts, or 98.8 per cent, of ferrous tantalate, Fe(Ta03) c tapiolite.

It is interesting to note that Rammelsberg 1 gives three analyses 

of "tantalite" from Kimito, Finland, that contain respectively 6.81, 

9.67, and 9.14 percent of Sn02 . Though it is not possible to decide 

whether the material analyzed was tantalite or tapiolite, I believe 

it is more probably the latter. If this belief is correct, the samples 

present an additional instance of the isomorphism of tapiolite and 

cassiterite.

An analysis of supposed ixiolite from Wodgina in western Australia gave Simpson 2 the results shown in the table below. The 

mineral occurs in "indistinct crystalline aggregates/.' and though its 

identification as a tetragonal mineral is therefore not determined, 

Simpson regards it as related to the ixiolite from Finland. Its 

density is 7.36.

Analysis and ratios of ixiolite (?)from Australia.

Ta05 Cb2A .................................................

Sn02 . .................................................

MnO...................................................

FeO....................................................

CaO....................................'...:...........

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

Ign .....................................................

Per cent.

70.49

7.63

8.92

10. 87.

1.34

. .42

.37

.18

100. 22

Ratio.

0 1591

. 029J- ib5

.059

.1531 ,}9

.oig/- 1 ^

From the above ratios the ixiolite (?) can be deduced to be of the 

composition shown below, the small amount of iron present being 

taken with the manganese. As can be seen from the ratios the

1 Rammelsberg, C. F., Handb. Mineralchemie, 1860, p. 391.

2 Simpson, E. S., Further occurrences of tantalum and niobium in western Australia: Proc. Australian 

Assoc. Adv. Sci., 1909, vol. 12,1910, p. 310.
20 MINERALOGICAL NOTES SERIES 2.

(MnO + FeO) is insufficient to take up all the (Ta205 + Cb205 ), so that, 

assuming accuracy of the analysis, it becomes necessary to assume 

the presence of the group (SnO) (Ta03 )2 . On this basis the ratios 

indicate:

29 parts, or 9.9 per cent, of Mn(Cb03 )2 . 

143 parts, or 74.0 per cent, of Mn(Ta03 )2 . 

16 parts, or 9.6 per cent, of (SnO) (Ta03 )2 . 

21.5 parts, or 6.5 per cent, of (SnO) (Sn03).

Assuming, however, that the (Mno + FeO) exactly balances the 

(Ta2 05 + Cb2 05 ), as would happen with only a slight change in the 

analytical figures, the composition of the sample can be expressed 

more simply as:

29 parts, or 9.8 per cent, of Mn(Cb03 )2 . 

159 parts, or 81.3 per cent, of Mn(Ta03)2 . 

29.5 parts, or 8.9 per cent, of (SnO) (Sn03 ).

Either interpretation agrees with the analysis and both are in consonance with the character of the compounds propounded as forming, 

either singly or in isomorphous mixture, the several members of the 

rutile group. It is uncertain whether the mineral here described 

belongs to this group or to the orthorhombic columbite-tantalite 

group. If it is a member of this group, the discussion of it should 

also be placed under the heading "Isomorphous mixtures of more 

than two of the primary compounds." On account of the uncertainty 

as to whether it really belongs anywhere in the group no special emphasis is laid on the predominance of MnO replacing FeO. Should it be 

definitely determined that the mineral is tetragonal, like rutile, and not 

orthorhombic, the list of chief primary compounds would have to be 

increased by the addition of manganous tantalate, Mn(Ta03 ) 2 and 

that of the minor primary compounds by the addition of manganous 

columbate, Mn(Cb03 ) 2 .

A cassiterite with nearly 9 per cent Ta205 was described from 

Finland and named ainalite by A. E. Nordenskiold. Its analysis 

is given below in the first column and repeated in the second column,- 

with the iron oxide given as FeO. The ratios are given in the third 

column.

Analysis and ratios of ainalite from Finland.

SvO2 .. ...........................................

Ta205 .................. .........................

Fe208 ............. :.............................

FeO.............................................

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

Per cent.

88.95

8.78

2.04

.78

100. 55

Per cent.

88.95

8.78

1.84

.78

100. 35

Ratio.

0.589

.020

.026
THE EUTILE GROUP. 21

The ratios indicate the following composition:

291.5 parts, or 88.3 per cent, of stannyl stannate (SnO)(Sn03) cassiterite. 

20 parts, or 10.4 per cent, of ferrous tantalate, Fe (Ta03 )2 tapiolite. 

6 parts, or 1.3 per cent, of.ferrous etannate, Fe(Sn03 )2 .

Several other cassiterites are given as containing from 2 to 5 per 

cent tantalic acid, but their analyses are too imperfect to warrant 

further discussion.

A cassiterite from Mecklenburg, N. C., gave Headden 1 the results 

shown in the table below. The density is 6.77.

Analysis and ratios of cassiterite from Mecklenburg, N. C.

'

Sn02 ... ................................... ................

FeO. .......................................................

Ta205 ----- .................................................

Per cent.

95.18

1.11

3.82

100. 11

Ratio.

0.630

.015

.009

From the above values the composition of the cassiterite is deduced to be as follows:

9 parts, or 4.6 per cent, of ferrous tantalate, Fe (Ta03)2 tapiolite. 

6 parts, or 1.3 per cent, of ferrous stannate, Fe(Sn03 ). ° 

312 parts, or 94.1 per cent, of stannyl stannate (SnO)(Sn03) cassiterite.

A cassiterite from the Etta mine, South Dakota, likewise analyzed 

by Headden gave the following percentages and ratios. Its density 

is 6.62. In Headden's analysis the iron is reported as 1.80 per cent 

Fe203, and this has been changed to the corresponding percentage 

of FeO.

Analysis and ratios of cassiterite from South Dakota.

Sn02 . .....................................................

FeO........................................................

Ta205 . .....................................................

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

Per cent.

94.36

1.62

2.42

1.00

99.58

Ratio.

0.625

.023

.005

From the above values the composition of this cassiterite is expressed as:

5 parts, or 2.5 per cent, of ferrous tantalate, Fe (Ta03 )2 tapiolite. 

18 parts, or 4.1 per cent, of ferrous stannate, Fe(Sn03 ). 

303.5 parts, or 93.3 per cent, of stannyl stannate (SnO)(Sn03) cassiterite..

1 Headden, W. P., Mineralogical notes, No. Ill: Proc. Colorado Sci. Soc., vol. 8,1906, p. 167.
22 MINERALOGICAL NOTES SERIES 2.

Both these cassiterites approach ainalite, which contains a tittle 

more Ta205 than either of the American cassiterites.

A cassiterite from the Greenbushes, Australia, contains, according 

to Simpson, 1 1.76 per cent Ta205 and 0.61 per cent iron oxide, etc.

The following summary of the isomorphous mixtures of tapiolite 

and cassiterite seems to indicate that their miscibility with each 

other is very slight. Further examination of natural specimens 

will probably show, however, that their miscibility is complete.

Isomorphous mixtures of tapiolite and cassiterite.

Analyst.

Nordenskiold .........

Locality.

Skogbole, Norway. ..............

Finland. .......................

Mecklenburg, N. C...............

Ferrous 

tantalate 

(tapiolite).

Per cent. 

98.8

93 to 90

691. 1

10.4

4.6

2.6

Stannyl stannate (cassiterite).

Per cent. 

1.2

6.81 to 9.67

8.9

88.3

Q4 1

c 93. 3

a See p. 19 for description of this mineral.

6 Includes 81.3 per cent manganous tantalate (MnTa03 ) and 9.8 per cent manganous columbate (MnCb 03).

c There is also present in the mineral 4.1 per cent ferrous stannate.

o

STANNYL STANNATE AND TITANYL TITANATE (CASSITERITE

AND RUTILE).

A peculiar occurrence of elongated twins, reacting for both titanium 

and tin, was described by M. von Miklucho-Maclay.2 ' If this occurrence is confirmed, the mineral may represent an admixture of rutile 

and cassiterite, a possibility entirely in accord with the facts.

TITANYL TITANATE (RUTILE) AND FERROUS TITANATE.

Three analyses of rutile from Graves Mountains, Ga., described 

as large black-brown prisms, pure and homogeneous, are given 3 in 

columns 1, 2, and 3 of the following table.

The average of these three analyses is shown in column 4; and by 

changing the values for Fe203 into the corresponding figures for ferrous oxide, 4 the results in column 5 are obtained, from which the 

ratios (under 6) are calculated.

iQp.cit., p.310.

2 Rutil und Zinnstein im Greifensteiner Granit (Ehrenfriedersdorf): Neues Jahrb., vol. 2, 1885, p. 88.

3 Pfeil, Karl, Ueber die Aufschliessung der Silikate und anderer schwer zersetzbarer Mineralien mit 

Borsaure-anhydrid: Centralbl. Min., Geol. u. Pal., 1902, p. 143.

4 The assumption that the iron is really present as FeO and not as FeaOs depends, of course, on the 

supposed purity of the material.
THE RUTILE GROUP. 

Analyses and ratios of rutile from Georgia.

23

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

Feo03 .........................

Feb.*........... ..............

1

97.64

2.61

100. 25

Analyses

2

97.22

2.62

99.84

3

97.52

2.64

100. 16

Average.

4

97.46

2.62

100. 08

Average.

5

97.46

2.36

99.82

Ratio.

6

1.218

.033

From these values the composition is found to be:

33 parts, or 5.0 per cent, of ferrous titanate, FeTi03 . 

593 parts, or 95.0 per cent, of titanyl titanate (TiO) (Ti03 ) rutile.

An analysis of a jet-black rutile from St. Peter's Dome, Colo., 

gave * the results shown in the following table. The crystal form is 

that of rutile with dominant {111}; twinning not mentioned. Measurements "give results with the reflection goniometer agreeing 

closely with the calculated angles for this species [rutile]". Considering the Si02 and H20 as extraneous, the Ti02 and FeO give the ratios 

shown below:

Analysis and ratios of rutile from St. Peter's Dome, Colo.

TiO................. .........................................

FeO........................................................

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

H20.......................... ...............................

Per cent.

94.93

3.77

1.37

.71

100. 78

Ratio.

1.187

.052

The composition of this rutile is, therefore:

52 parts, or 8.0 per cent, of ferrous titanate, FeTi03 . 

567.5 parts, or 92.0 per cent, of titanyl titanate (TiO) (Ti03) rutile.

The density of the sample is 4.288, which is somewhat higher than 

that of rutile (4.2).

An iron-black rutile in distorted pyramids {111}, but not twinned,, 

from West Cheyenne Canyon, El Paso County, Colo., gave the 

analysis shown below.2 Recalculating the iron reported as Fe2O3 

to FeO, the analysis is as given in the second column; the ratios 

obtained from these figures are given in the third column.

1 Smith, W. B., Mineralogical notes No. Ill: Proc. Colorado Sci. Soc., vol. 2,1887, p. 175.

2 Genth, F. A., and Penfleld, S. L., Contributions to mineralogy, No. 54, with crystallographicnotes: Am. 

Jour. Sci., 3d ser., vol. 44,1892.
.24 MINEEALOGICAL NOTES SERIES 2. 

Analysis and ratios ofrutilefrom El Paso County, Colo.

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

Sn02 . ...........................................

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

FeO. ..................................... .....

Per cent.

91.96

1.40

6.68

100. 04

Per cent.

91.96

1.40

6.01

99.37

Ratio.

1.149

.009

.083

From the values of the ratios, the composition of this sample is as 

follows:

4.5 parts, or 1.3 per cent, of stannyl stannate (SnO) (Sn03) cassiterite. 

83 parts, or 12.8 per cent, of ferrous titanate, Fe (Ti03). 

533 parts, or 85.9 per cent, of titanyl titanate (TiO) (Ti03) rutile.

The density of the sample is given as 4.249, which seems to be a 

little low.

A nigrine from Bernau, Bavaria, is described by Rammelsberg * 

who gives the following analysis (first column), which is repeated in 

the second column with the ferric iron oxide changed to the corresponding amount of ferrous oxide. The density of this material is 4.41.

Analysis and ratios of nigrine from Bavaria.

Ti02 ....... ..................;.................

FejOj............ ..............................

FeO..........................................

MgO... .......... '...........-....................

Per cent.

89.49

11.03

.45

100. 97

Per cent.

8Q 4Q

9.93

.45

99.87

Ratio.

1.118

' 1101 121

. on/- m

The ratios indicate the following composition:

121 parts, or 18.8 per cent, of ferrous titanate, Fe (Ti03).

498.5 parts, or 81.2 per cent, of titanyl titanate (TiO) (Ti03) rutile.

Rammelsberg 2 mentions two other analyses of nigrine. The first 

(from Ohlapian, Siebenburgen, Transylvania)- has, according to 

Klaproth, the composition shown below in the first column. With 

the iron and manganese oxides changed to the bivalent condition, the 

analysis is repeated in the second column. The density is given as 

4.445 (Klaproth) and as 4.4-4.5 (Breithaupt). The mean value is 

4.45.

1 Rammelsberg, C. F., Handb. Mineralchemie, Zweite Aufl., I. Theil, 1875, p. 169.

2 Rammelsberg, C. F., Handb. Mineralchemie, I860, p. 1009.
THE BUTILE GROUP. 

 Analysis and ratios of nigrine from Transylvania.

25

TiO..............................................

Fe203 . ...........................................

FeO

Mn203 . ..........................................

MnO. ............................................

Per cent.

84

14

2

100

Per cent.

84.0

12.6

1.8

98.4

Ratio.

1.05

.17

.03

The ratios may be interpreted as follows:

20 parts, or 31 per cent, of ferrous titanate, Fe (Ti,03).

42.5 parts, or 69 per cent, of titanyl titanate (TiO) (Ti03) rutile.

The second analysis given is by Muller, who analyzed nigrine from 

Bariern with the results shown below:

Analysis and ratios of nigrine from Bariern.

Tin

FeO........................................................

Per cent.

86.2

14.2

100.4

Ratio.

1.08

.20

This would correspond to a mixture in the following proportions:

20 parts, or 30 per cent, of ferrous titanate, Fe (Ti03 ).

44 parts, or 70 per cent, of titanyl titanate (TiO) (Ti03) rutile.

The composition of the two samples is very close but the density 

given for the last sample is high, namely 4.56. It is not improbable 

that some columbium and tantalum were present in each sample, 

which would account for the rather high densities.

The analyses of iserite from Iser, Bohemia, given by Janovsky, are 

repeated in the first and second columns below, the average being 

given in the third column and the ratios in the fourth.

Analysis and ratios of iserite from Bohemia.

TiO

FeO2. ...............................

MnO.................................

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

Cba06 -------..-------...--...----

TaA............ .....................

Per cent.

70.03

28.77

Not det.

. Not det.

Not det.

Per cent.

68.99

28.57

1.41

.32

1 .44

'

99.73

Per cent.

69.51

28.67

1.41

.32

.44

100. 35

Ratio.

0.869

1 .426

.002
26 ' MINER ALOGICAL NOTES SERIES 2.

In calculating the ratios from the average analysis, the (MnO + 

MgO) are included with the FeO, and the mixture of (Cb205 + Ta205 ) 

is arbitrarily considered as pure Cb205 .

The composition of iserite is from these analyses calculated to be 

as follows:

2 parts, or 0.6 per cent, of ferrous columbate, Fe (Cb03 )2 . 

424 parts, or 64.0 per cent, of ferrous titanate, Fe (Ti03 ). 

222.5 parts, or 35.4 per.cent, of titanyl titanate, (TiO) (Ti03 ) rutile.

Considering the formula of rutile in the form here given, the 

mineral under consideration contains an excess of ferrous titanate. 

The density of iserite is given as 4.52. Knowing the density of 

ferrous columbate l (at least approximately) and also that of rutile, 

the density of pure ferrous titanate may be calculated. Taking the 

density of rutile as 4.2 and that of the ferrous columbate present in 

this iserite as 6.5 (Brogger gives 6.45 for his "mossite" with 

Cb : Ta = l : 1), there is obtained for the density of ferrous titanate 

the value 4.7. This is, however, lower than the values obtained 

from nigrine, as is shown in the table below.

The isomorphous mixtures of titanyl titanate (rutile) and ferrous 

titanate are shown in the following table:

Mixtures of titanyl titanate (rutile) and ferrous titanate.

Locality.

Georgia. ..............................

St. Peters Dome, Colo. .................

EL Paso County, Colo. . .................

Bavaria. ..............................

Barien. . ..............................

Ferrous 

titanate.

Per cent. 

5.0

8.0

12.8

18.8

31.0

30.0

64.0

Titanyl 

titanate 

(rutile).

Per cent. 

95.0

qo n

85.9

81.2

69.0

70.0

35.4

Density.

4.288

4.249

4.41

4.45

4.56

4.52

Calculated 

density of 

ferrous 

titanate.

^ 3

5.1

5.3

5.0

5.4

4.74

All the calculations of the density of ferrous titanate, except the 

last, give values of 5 or over. The last, the value obtained from 

iserite, supposedly of correct determination, gives a figure much 

-lower than any of the others. The density of ferrous titanate, 

therefore, can not be given any more definitely than 5 ± .25.

TITANYL TITANATE (RUTILE) AND TITANYL VANADATE (?).

The possible occurrence of titanyl vanadate as an additional 

member of the minor primary compounds is indicated by .a rutile 

from Roanoke County, Va. This rutile is said to carry 5 percent

1 The small amount present would not have an effect greater than that due to experimental error.
THE EUTILE GROUP.

V205 and a qualitative test, made at the suggestion of Mr. F. L. Hess, 

showed a decided reaction, for vanadium. The presence of this 

vanadium can be most readily explained by the assumption of the 

presence of the molecule (TiO)(V03 ) 2 in isomorphous mixture with 

(TiO)(Ti03 ).

STANNYL STANNATE (CASSITERITE) AND FERROUS STANNATE.

The only analyses of iron-rich cassiterites that I could find are 

those made by Genth l on Mexican tinstones. Through the courtesy 

of Mr. F. L. Hess, of the Geological Survey, I was enabled to examine 

cassiterites similar to those described by Genth. On examining 

crushed fragments under the microscope the material appeared to 

be homogeneous, and no admixed ferric oxide could be seen. I therefore believe that iron is a fundamental ingredient of at least some of 

these ferriferous cassiterites and, assuming that it is present in the 

ferrous condition, instead of in the ferric, as reported by Genth, I have 

recalculated his iron determinations and given them here in the corresponding ferrous state. Not all Genth's analyses are reproduced, 

for many are very similar and one of such suffices. The numbers of 

the analyses are those given by him.

Analyses of ferriferous cassiterites from, Mexico.

8n02 .. ................................

FeO..................................

A8205 .................................

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

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

Igu...................................

Ib

92.84

3.71

2.70 '.34

o 99. 59

II

93.98

5.06

.23

' .24

0 99. 51

v.

86.99

10. 40

Trace.

.11

.57

.20

« 98. 27

vb

86.81

11. 46

.52

.34

« 99. 13

a If the iron is actually present as FeO the number giving the "ignition" value should be increased by 

the amount of oxygen required to oxidize the ferrous iron. This would raise the total values to 99.90, 

100.02, 99.31, 100.28, respectively.

The ratios deduced from the above analyses, neglecting CuO, Si02, 

and ignition, are as follows:

Ratios of ferriferous cassiterites from Mexico.

Sn02 ...................... ............

FeO..................................

Ib

0. 615

.051

II

0. 622

.070

va

0.576

.144

vb

0.575

1 £><}

1 Genth, F. A., Proc. Am. Philos. Soc., vol. 24,1887, p. 26.
MlffEBALOGlCAL NOTES SERIES 2.

TT

These ratios give the following composition of the four samples:

nf/ 51 parts, or 11.8 per cent, offerrous stannate, Fe(Sn03 ).

OI\282 parts, or 88.2 per cent, of stannyl stannate (SnO)(SnO3) cassiterite.

nff ^ parts, or 15.8 per cent, of ferrous stannate, Fe(Sn03 ). 

\276parts, or 84. 2 per cent, of stannyl stannate (SnO)(Sn03 ) cassiterite.

^ parts, or 32.3 per cent, of ferrous stannate, Fe(Sn03). 

216 parts, or 67.7 per cent, of stannyl stannate (SnO)(Sn03 ) cassiterite.

159 parts, or 36.1 per cent, of ferrous stannate, Fe(Sn03 ).

> of 8tannyl stannate (SnO)(Sn03 ) cassiterite.

v v a r,aiata consists

The last two samples, isomorphous mixtures of ferrous stannate, 

Fe(SnO3 ), and stannyl stannate (SnO)(Sn03 ), include an amount of 

the first-named salt equal to about one-third of their total composition.

Two more analyses of these ferriferous cassiterites, shown below, 

have as their most noteworthy feature the presence of small amounts 

of As205 .

greater than in the two analyses quoted below. 

are given the ratios deduced from them.

In certain other varieties the amount of As205 s even

With the analyses

Analyses and ratios of cassiterite from Mexico.

Sn02 :. ................................

FeO................... ...............

As2O5 .......... .......................

ZnO............ .......................

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

SiO? ...................................

Ignition. ...............................

V

Per cent.

92.26

4.12

1.25

.57

Trace.

.44

.26

98.90

I

Ratio.

0.611

.057

.006

.007

r

Per cent.

92.09

4.90

9 11

.66

.07

99.83

V

Ratio.

0.610

.068

.009

In considering the composition of these two cassiterites, it becomes 

necessary to admit two compounds hitherto not found in the list of 

primary compounds. The new compounds are zinc arsenate 

ZnO.As205 , and ferrous arsenate, FeO.As205 , or, as written in conformity with the other salts of these minerals, Zn//(As03) 2 and 

Fe"(As03) 2 . These compounds I could not find described in the 

literature, but from a consideration of other series of polymorphic 

forms of the general rutile group formula, R"(R,03)", the validity of 

the assumption that Zn"(AsO3) 2 and Fe"(As03) 2 are isomorphously 

related to Fe"(Ti03) 2 and its related compounds is strongly indicated 

by the composition of such minerals as lewisite and derbylite.
THE BUTILE GROUP. 29

The two cassiterites whose analyses were just given are shown by 

the ratios to be made up of the substances and in the proportions 

shown below.

r 6 parts, or 1.9 percent, of zinc arsenate, Zn (As03 )2 . 

VI consists of] 57 parts, or 12.9 per cent, of ferrous stannate, Fe (Sn03 ).

1277 parts, or 85.2 per cent, of stannyl stannate. (SnO) (Sn03 ) cassiterite.

1

9 parts, or 2.8 per cent, of ferrous arsenate, Fe (As03 )2 . 

59 parts, or 13.5 per cent, of ferrous stannate, Fe (Sn03 )2 . 

271 parts, or 83.7 per cent, of stannyl stannate, (SnO) (Sn03 ) cassiterite.

The isomorphous mixtures of stannyl stannate (cassiterite) and 

ferrous stannate, as developed in the preceding pages, are summarized 

in the following table:

Mixtures of ferrous stannate and stannyl stannate (cassiterite).

Analyst.

Headden a ..........

Genth.. .............

Do...............

Do...............

Do...............

Do...............

Do...............

Locality.

Finland. .............................

.....do...............................

.....do...............................

.....do...............................

.....do...............................

.....do...............................

Ferrous 

stannate.

Per cent. 

1.3

1.3

4 1

11.8

12.9

13.5

15.8

32.3

36.1

Stannyl 

stannate 

(cassiterite).

Per cent. 

*>88.3

c94. 1

dW 3

88.2

«85.2

/83.7

84.2

67.7

63.9

« Described on p. 21.

6 This mineral also includes 10.4 per cent of tapiolite.

c This mineral also includes 4.6 per cent of tapiolite.

d This mineral also includes 2.6 per cent of tapiolite.

e This mineral also includes 1.9 per cent of zinc arsenate.

/ This mineral also includes 2.8 per cent of ferrous arsenate.

ISQMORPHOUS MIXTURES OF MORE THAN TWO OF 

THE PRIMARY COMPOUNDS.

The mixtures of more than two of the primary compounds include 

striiverite, ilmenorutile, and some of the Mexican cassiterites analyzed 

by Genth.

STRttVERITE.

Striiverite was described by Prior and Zambonini in 1908 and, as 

they state at the end of their paper, the name striiverite is proposed 

"for those members of the series which are rich in tantalic acid." 

These minerals-are regarded "as essentially solid solutions of the 

tapiolite or mossite molecule Fe[(Ta, Nb)03]2 with the rutile molecule
30 MIKERALOGICAL NOTES SEBIES 2.

TiO.Ti03 ." Such a conception, however, entirely ignores the slight 

but constant excess of FeO in the analyses. The tetragonal crystals 

of striiverite resemble those of rutile in habit and in their angular 

values. Prior and Zambonini state: "Of frequent occurrence are 

crystals elongated along the edge s:£ = ['(lll):(lTl)]; most of these 

appear to be twins on a face of the form {101}, like the well-known 

twins of ilmenorutile, tapiolite, and mossite, and also of rutile from 

certain localities." The value deduced for the c axis is 0.6456. 

(Compare the values given on p. 12.)

The following are the analytical figures given by Prior and Zambonini for striiverite from Italy:

Analyses and ratios of striiverite from Italy.

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

Cb2O6 .. .............................

Ta!o rS?5 ::::::::::::::::::::::::::::::

MnO............... ..................

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

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

Analysis.

Per cent. 

41.09

| 46. 94

11.15 

Trace. 

' .51 

.17

Per cent. 

41.32

46.98 

11.62

Average.

Per cent. 

41.20 

/ 23. 48 

1 23. 48 

11.38 

Trace. 

.51 

.17

100. 22

Ratio.

0.515 

.088] 

.053J 

.158

.009 

.004.

 .141 

.171

Inspection of the ratios shows that there is an excess of FeO over 

the amount required to combine with the Cb205 and Ta205 . If, 

however, we assume the presence of sufficient ferrous titanate to take up 

all the remaining FeO, the interpretation of the above average analysis 

becomes simple and accurate. The ratios show, in fact, that the 

material analyzed is an isomorphous mixture of the four minerals in 

the proportions shown below.

88 parts, or 29.9 per cent, of ferrous columbate, Fe (Cb03)2 . 

53 parts, or 27.4 per cent, of ferrous tantalate, Fe (Ta03 )2 tapiolite. 

17 parts, or 2.6 per cent, of ferrous titanate, Fe (Ti03 ). 

249 parts, or 40.1 per cent, of titanyl titanate, (TiO) (Ti03 ) rutile.

For an isomorphous mixture of the proportions shown above, the 

calculated composition is given below in comparison with the striiverite analysis. The agreement of the calculated values with those 

in the analysis is very close, so that the explanation offered is consistent. The direct comparisons with the analytical figures clearly 

bring out the correctness of the view here proposed.

Two determinations of the density of striiverite give 5.54 and 5.59, 

from which a mean value of 5.57 may be taken.
THE BUTILE GROUP. 31 

Calculated percentages of struverite from Italy compared with analysis.

Tin cb2o....... ..I............................................. TO n

F:fc::::::v:::::::::::::::::::::::::::::::::::::::::::::

MnO........................................................

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

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

Calculated.

41.41

23.62

23.54

11.43

100. 00

Analysis.

41.20

23. 48

23.48

11.38

Trace.

.51

.17

100. 22

An occurrence of struverite from the Etta mine, South Dakota, 

has been described by Hess and Wells. 1 According to their analysis, the South Dakota mineral, unlike the Italian struverite, fits the 

definition of struverite given by Prior and Zambonini.

The analysis of struverite from South Dakota and the ratios calculated therefrom are given below. The close relation in crystalline 

form of tin's mineral to rutile is described in the paper referred to.

Analysis and ratios of struverite from South Dakota.

Tin

Sn02 . .....................................................

FeO. .................................................... Ta n

CbA----------------------- -------. .....................

Per cent.

49.0

1.3

7.3

35.7

6.7

100.0

Ratio.

0. 613\ r99 .009/- 622

. 101 . 101

081ll06

. 025J- 1Ub

The ratios approximate the formula FeO.(Ta,Cb) 2 05 .6H20, but 

there is no warrant for assuming the existence of such a compound. 

The composition may be interpreted according to the following tabulation, which shows the mineral to be an isomorphous mixture of the 

primary compounds of the rutile group, tapiolite and rutile largely 

predominating.

25 parts, or 8.4 per cent, ferrous columbate, Fe(Cb03 )2 . 

81 parts, or 41.4 per cent, ferrous tantalate, Fe(Ta03 )2 tapiolite. 

306.5 parts, or 48.8 per cent, titanyl titanate (TiO) (Ti03 ) rutile. 

4.5 parts, or 1.4 per cent, stannyl stannate (SnO) (Sn03 ) cassiterite.

This struverite is the only mineral of this entire group containing 

Cb, Ta, Fe, and Ti in quantity in which no ferrous titanate is present.

1 Hess, F. L., and Wells, R. C., An occurrence of struverite: .Am, Jour, Sci., 4th ser., vol. 31,1911, p. 432.
32 MINEKALOGICAL NOTES SERIES 2.

That the percentages of the primary compounds closely represent 

the true composition of the mineral can be shown in another way, 

namely, by calculating back the percentage values of the different 

oxides and comparing them with the analytical figures. The values 

obtained should, of course, agree exactly or nearly so 1 with the analytical figures from which the percentages of the primary compounds 

were obtained. The calculated composition is compared with the 

analytical figures in the table below:

 . Calculated percentages of striiverite from South Dakota compared with analysis.

TiOa ................................. ........................

SnO............................... .........................

FeO

TajOg.........:.. ........................................... Cb2o5 . ......................................:..............

Calculated.

49.0

1.3

7.3

35.8

6.6

100.0

Analysis.

49.0

1.3

7.3

35.7

6.7

100.0

A black rutile or nigrine from South Dakota with a brilliant and 

metallic luster was described by Headden and Pirsson. 2 The streak 

was grayish black, the hardness 6, and the density 5.294. The measurements of the crystals agreed well with the angles of rutile, but the 

value given for the density-is entirely too high for a rutile of the 

composition given by Headden and Pirsson. As their material was 

similar to that analyzed and described by Hess and Wells, their 

analytical figures are doubtless entirely wrong for the Ti02 .

Their analyses gave the values shown under 1 and 2, but no ratios 

are deduced because the value given for Ti02 is considered erroneous.

Analyses of supposed rutile from South Dakota.

Ti08 .............. ...................... '..............,.....

SnO,.. ....... ...............................................

FeO.......................................................

MnO.l. ....................................................

"

1

90.78

1.32

8.10

Trarp

100. 20

2

90.80

1.38

7.92

Trace.

100. 10

That the mineral described by Headden and Pirsson is similar to 

that analyzed by Wells is shown by comparison of the two analyses,

1 Slight differences will be found because of Impurities in the mineral which are given in the analysis 

but are not figured in the ratios, and because the calculations are not carried to a sufficient number of 

decimals.

2 Headden, w. P., and Pirsson, L, V., On black rutile from the Black Hills: Am, Jour, Scl, 3d.ser., vol. 

14,1891, p. 249,
THE EUTILE GROUP. 33

in which the constituents other than Ti02 + Cb205 + Ta205 agree 

closely. The densities of the two minerals also correspond well.

Comparison of analyses of South Dakota mineral.

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

Cb205 ........................................... .........

Ta205 . ....................................................

SnO,.... .................................................

FpO

MnO......................................................

Average 

of analyses land 2.

1

90. 79

1.35

8.01

Trace.

100. 15

Wells 'a 

analysis.

I

4Q 01

6. 7 [91. 4

OK 7

1.3

7.3

100.0

Average density of mineral analyzed by Headden and Pirsson, 5.294. 

Density of mineral analyzed by Wells, 5.25.

ILMENOBTJTILE.

Ilmenorutile is found in tetragonal crystals similar to rutile in 

angles and frequently twinned after (101), being often elongated 

parallel to the edge (111): (111).

Ilmenorutile from the Ilmen Mountains was analyzed by Prior. 

His results and ratios are given below. 1 The density of his material 

is 5.14.

Analysis and ratios of ilmenorutile from the Ilmen Mountains.

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

Cb205 .... ................................................

Ta205 . ....................................................

FpO

Per cent.

53.04

21.73

14.70

10.56

Trace.

100. 03

Ratio.

0.663

.0811 U4

. 033f 114

.147

The ferrous iron is again in excess of that required for the 

columbate and tantalate, and the interpretation of the analysis 

shows four of the primary mineral species to be present in quantity. 

The composition is indicated to be as follows:

33 parts, or 5.0 per cent, of ferrous titanate, FeTi03 . 

81 parts, or 27.5 per cent, of ferrous columbate, Fe(Cb03 ) 2 .. 

33 parts, or 17.0 per cent, of ferrous tantalate, Fe(Ta03 ) 2 tapiolite. 

315 parts, or 50.5 per cent, of titanyl titanate, (TiO) (Ti03 ) rutile.

i An earlier analysis given by G. T. Prior (Mineralog. Mag., vol. 15, 1908, p. 

because in it the CbjOs+TajOs were not separated.

23590° Bull. 509 12 3

is excluded here
34 MINERALOGICAL NOTES SERIES 2.

. The calculated values for the composition, as given in 'the table 

above, are shown with the analysis repeated in the table below.

Calculated percentages of ilmenorutile from the Ilmen Mountains compared with analysis.

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

Cb205 ... ..................................................

Ta205 ... ....................................................

FeO ......................................................

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

Calculated.

 53. 13

21.66

14.61

10.60

100. 00

Analysis.

53.04

21.73

14.70

10.56

Trace.

100. 03

An analysis of ilmenorutile from Evje Kirschspiel, in Saetersdal, 

as described by Brogger * and corrected by Prior 2 gave the following results:

Analysis and ratios of ilmenorutile from Saetersdal.

TiO2 .... . ................................................

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

Cb205 ...................................................

Ta205 .. ..................................................

Feb....................................................

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

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

Per cent.

54.50

.23

33.02

.43

11.58

.04

.22

100. 02

Ratios.

0.681

ml

.ooi/- 125

.161

Here, again, the ferrous iron is in excess and it becomes necessary, 

as suggested by Brogger, to consider the admixture of the molecule 

FeTi03 . The composition of the mineral can then be expressed as 

follows:

36 parts, or 5.5 per cent, of ferrous titanate, Fe(Ti03). 

124 parts, or 42.1 per cent, of ferrous columbate, Fe(Cb03)2 .

1 part, or 0.5 per cent, of ferrous tantalate, Fe(Ta03) 2 tapiolite. 

322.5 parts, or 51.9 per cent, of titanyl titanate, (TiO) (Ti03) rutile.

A comparison of the calculated composition, as given above, with 

the analysis, is shown n the following table, in which is also given 

the nearly identical analysis of ilmenorutile from Ansel, near Tvedestrand, given by Brogger and corrected by Prior:

1 Videnskabs-Selskabets Skrifter. Math, naturw. Kl., 1906, no. 6.

2 Prior, G. T., op. cit., p. 86.
THE RTJTILE GROUP. 

Calculated percentages compared with analyses of ilmenorutile.

35

TiOCb2o5 .-- -..-.--.-..-.-...-.. -- -- --- ------

Ta205 - .---- ----- ...............................

FeO... . .........................................

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

MnO. ...........................................

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

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

Calculated .

54.69

33.23

.44

11. 6'4

100. 00

Ilmenorutile 

from 

Evje.

54.50

33.02

.43

11.58

.23

.04

.22

100. 02

Ilmenorutile 

from 

Ansel.

54.50

33.49

11. 68

.05

Trace.

Trace.

.28

100. 00

Ilmenorutile from Iveland, Norway, was also analyzed by Prior. 

Tantalum could not be detected, so no admixture of tapiolite is 

present. The low summation is ascribed to a probable slight loss 

of columbium.

Analysis and ratios of ilmenorutile from Iveland.

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

Cb2 05 - ....................................................

FeO... ...................................................

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

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

Per cent.

54.57

32. 15

12. 29

.11

Trace.

99. 12

Ratio.

0.682

.120

.170

It can at once be seen that the ferrous iron is greatly in excess of 

the columbic oxide, so that a relatively large amount of ferrous 

titanate must be present. The ratios lead to the following interpretation:

120 parts, or 41.1 per cent, of ferrous columbate, Fe(Cb03)2 . 

50 parts, or 7.7 per cent, of ferrous titanate, Fe(Ti03). 

316 parts, or 51.2 per cent, of titanyl titanate, (TiO) (Ti03) rutile.

A comparison with the analysis of the values calculated from this 

composition is given below:

Calculated percentages compared with analysis of ilmenorutile from Iveland.

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

Cb205 - ..................................................... \

FpO

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

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

Calculated.

55.20

3-2. 4.1.

12. 39

100. 00

Analysis.

54.57

32. 15

12.29

.11

Trace.

99.12
36 MINERALOGICAL NOTES SERIES 2.

ARSENICAL CASSITERITE.

Three analyses of the Mexican cassiterites * show them to be 

practically free from iron, but to contain considerable As205 and 

ZnO. In fact, the ZnO is always in molecular excess to the amount 

of As205 required to form Zn(As03 ) 2 , so that the small amounts of 

ZnO ( +FeO) left over are combined with sufficient tin to form the 

compound Zn(Sn03 ), whose acceptance in the list of primary compounds is as well grounded as is that of Fe(SnO3 ).

Analyses of cassiterite from Mexico.

-

Sn02 . ..........................................

FpO

ZnO. ...........................................

CuO. ........................................... AQ n

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

Ign.... . .........................................

VIII

92.50

.20

1.89

.16

4.56

.24

.26

99.81

IX

89.90

.09

2.43

.20

5.80

.55

.40

99.37

X

93.13

.18

2.71

.09

3.18

.43

.32

100. 04

Ratios of analyses of cassiterite from Mexico.

SnOa .. .....................................

FeO...... .................................

ZnO........................................

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

VIII

0.613

.0031

.023 .028

.002J

.020

IX

0.595

.001]

.030 .034

.003J

.025

X

0.617

' .0031

.033 .037

.OOlJ

.014

If the FeO and CuO are treated as ZnO, these ratios indicate the 

following composition for the above three samples:

20 parts, or 6.2 per cent, of zinc arsenate, Zn(AsOa )2 . 

8 parts, or 3.0 per cent, of zinc stannate, Zn(Sn03 ). 

302.5 parts, or 90.8 per cent, of stannyl stannate, (SnO) (Sn03) cassiterite.

VIII consists of.

IX consists of

X consists of

25 parts, or 7.8 per cent, of zinc arsenate, Zn(As03)2 . 

9 parts, or 3.1 per cent, of zinc 0 stannate, Zn(Sn03 ). 

293 parts, or 89.1 per cent, of stannyl stannate, (SnO) (Sn03) cassiterite.

14 parts, or 4.2 per cent, of zinc arsenate, Zn(As03)2 . 

23 parts, or 8.6 per cent, of zinc stannate, Zn(Sn03)2 . 

297 parts, or 87.2 per cent, of stannyl stannate, (SnO) (Sn03) cassiterite.

1 Analyzed by Genth, op. cit.
THE EUTILE GROUP. 37

One analysis shows proportionately a large amount of As2 05 , but 

the molecular amount of ZnO + FeO still exceeds the amount required to form (Zn, Fe) (As03) 2 . This analysis and the ratios derived 

from it are shown below:

Analysis of cassiterite from Mexico. a

SnOo. ............................'......................... Feo:.......................................... :............

ZnO ........................................................

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

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

Ign. ........................................................

Per cent.

84.30

1.39

2.96

Trace.

10.34

.30

.57

99.86

Ratio.

0.558

.019

.037

.045

a Genth's analysis VII b.

The composition of this sample is expressed by the following 

tabulation:

37 parts, or 11.6 per cent, of zinc arsenate, Zn(As03 ) 2 . 

8 parts, or 2.4 per cent, of ferrous arsenate, Fe(As03)2 . 

11 parts, or 2.5 per cent, of ferrous stannate, Fe(Sn03). 

273.5 parts, or 83.5 per cent, of stannyl stannate, (SnO) (Sn03) cassiterite.

CONCLUSION.

It has been shown that chemically all the minerals here described 

may be considered as isomorphous members of a series consisting of 

several distinct compounds or as mixtures of two or more of those 

compounds. All the mixtures have the same or nearly the same 

crystallographic values (tetragonal, c = 0.64 approximately), and 

nearly all possess the peculiar distorted twinning. That no morphotropic series "is at hand is shown by the constancy of the crystallographic axis c, and I believe that formulas such as FeO.(Ta,Cb) 2- 

O5 .4TiO2 for striiverite and FeO.(Cb,Ta) 205 .5Ti02 for ilmenorutile, 

as suggested by Prior and Zambonini, are incorrect, and that the 

writers who have proposed them fail to consider the obvious isomorphous relations of the much simpler (in composition) primary compounds. Prior and Zambonini state, however, that "closer agreement between the amounts found and calculated are obtained when 

we assume an admixture of the molecule FeTi03 (as suggested by 

Brogger) or of FeTi205 , molecules such "as may be present in the 

ferriferous rutiles. On this, assumption, the formula of ilmeno5 2 rutile from the Ilmen Mountains would be 3.5[FeO.(Cb=, Ta=) 2O5 .5-

Ti02] + FeTi2O5 , and of that from Iveland 2.4[FeO.Cb205 .5TiO2] + 

FeTi2O5 ." These formulas, however, contain compounds the ex-
38 ^ MINERALOGICAL NOTES SERIES 2.

istence of neither of which (FeO.Cb205 .5Ti02 , FeTi205 ) has been 

demonstrated. The evidence of the mutual isomorphous mixing in 

varying proportions of the primary constituents is so strong that I 

believe the simpler explanation here offered to be nearer the true 

one. I would therefore propose that of the different minerals and 

mineral mixtures comprising the rutile group, as I define it, the only 

names 1 that should be kept up as distinct mineral species are the 

three following:

Tapiolite, Fe(Ta03 )2 or FeO.Ta2Os . 

Rutile, (TiO) (Ti03) or Ti02 / 

Cassiterite, (SnO) (Sn03 ) or Sn02 .

In addition, the name ilmenorutile will serve, as a subspecies, to 

indicate those mixtures in which Fe, Ta, Cb, and Ti are present in 

quantity. Brogger's "mossite" is then only a columbium tapiolite. 

When the pure or nearly pure (tetragonal) iron columbate is found 

in nature, then a new name will be appropriate and necessary. 

Similarly, the compounds FeTi03 and FeSn03, when found in nature 

in a pure or nearly pure condition will be entitled to distinct new 

mineral names.

Nigrine and iserite are only iron rutile, ainalite is a tantalum 

cassiterite, and striiverite 2 the same as ilmenorutile. If it seems 

desirable, the various ilmenorutiles can be called columbium ilmenorutile, tantalum ilmenorutile, titanium ilmenorutile, iron ilmenorutile, and tin ilmenorutile, depending on which of these elements 

predominates in the composition of specimens.

The several cassiterites from Mexico analyzed by Genth can be 

called, to distinguish them from pure cassiterite, iron cassiterite, 

arsenic.or arsenical cassiterite, zinc cassiterite, etc. Such a system 

of nomenclature at once defines a variety for example, tantalum 

cassiterite means cassiterite containing tantalum. To give a new 

name for every variety of a known mineral would lead to such a 

multiplicity of names that any systematic scheme of nomenclature 

would be hopeless. The system here proposed is elastic enough to 

permit nearly all new finds to be referred to it.

A name should not be put forward or if proposed should not be 

accepted for a known mineral in which a small amount of some 

 other element is present, particularly where the presence of that 

element is due to isomorphous replacement. If a rutile contains 

several per cent of iron in combination, it should not be given a 

distinct name (like nigrine), but should be called what it really is, 

an iron rutile, or a ferriferous rutile. If a calcite contains a little

1 As additional members of this group, which rank as well-defined species, are to be added zircon, thorite, 

polianite, plattnerite and perhaps others. See footnote on p. 9.

2 Certainly the Italian striiverite has no claim for specific identity distinct from ilmenorutile.
THE RUTILE GROUP. 39

cobalt, it should not be called cobaltocalcite, but simply a cobalt 

calcite. Indiscriminate use of distinct names for mere varieties or 

for certain isomorphous mixtures opens up the possibility of an 

infinite number of names which would in time so complicate the 

science of mineralogy as to make it unfit for practical service.

The mineral names used in this discussion which it is believed have 

no claim for recognition as distinct mineral species and the descriptive 

terms proposed to replace them are as follows:

Mossite............................. columbium tapiolite.

Nigrine and iserite ................. .iron rutile.

Ainalite............................ tantalum cassiterite.

Striiverite'.......................... ilmenorutile.

»I here mean the Striiverite from Italy. The mineral from South Dakota would he called tantalum 

Ilmenorutile.
BARBIERITE, MONOCLINIC SODA FELDSPAR.

The existence of a monoclinic dimorphous form of albite isomorphous with orthoclase, was long ago suggested, but the presence of soda 

in orthoclase analyses has generally been otherwise explained, most t 

commonly by granting the presence of albite or an orthoclase. In a 

recent-paper by Barbier and Prost* analyses are given of feldspars in 

which the cleavage angle varies but a few minutes from 90° and in 

which soda is present in molecularly greater amount than the potash. 

The maximum soda content is reached in a feldspar from Kragero, 

Norway, in which only 1.15 per cent K20 was found.

Prof. Barbier was kind enough to send me some slides of the feldspar from Kragero which, according to his analysis, consists essentially of the soda compound. One of the slides, a basal section giving parallel extinction and appearing to be uniform, was uncovered 

and the feldspar washed free from Canada balsam. The mineral was 

then immersed in an oil with a refractive index of 1.530, and it was 

seen that the index of the mineral was considerably lower than that 

of the oil. If the orientation of the mineral .is the same as that of 

orthoclase a basal section would yield values for a and for 7-. As 

these were both found to be decidedly lower than 1.530, the section 

can not be albite. 2 Unfortunately the very small section was accidentally lost before its soda content could be verified microchemically.

Microscopic examination by Prof. Barbier showed that with one 

exception albite was not present in his specimens, and consequently 

the existence of a monoclinic soda feldspar isomorphous with orthoclase must be admitted. I propose to call this particular monoclinic 

soda feldspar barbierite, in honor of Prof. Barbier, who is a member 

of the faculty of the University of Lyon, France. He has recently 

published, in addition to the paper above cited, an article on the feldspar group in which he gives a definite chemical difference between 

orthoclase and microcline. 3 Further analyses of soda-rich orthoclases 

are given by him in a later paper. 4 The feldspar from Kragero is 

nearly pure barbierite.

1 Barbier, Ph., and Prost, A., Sur 1'existence d'un feldspath sodique monoclinique, isomorpbe de 

1'orthose: Bull. Soc. chim., 1908, III, p. 894.

2 For albite, a=1.529, r=l-539.

3 Barbier, Ph., Recherches sur la composition chimique des feldspaths potassiques: Bull. Soc. franc, 

mineral., vol. 31,1908, p. 152.

« Barbier, Ph. and Gonnard, F., Analyses de quelques feldspaths francais: Bull. Soc. frang. mineral., vol. 

33,1910, p. 81.

40
BARBIERITE, MONOCLINIC, SODA FELDSPAR. 41

Angel 1 recently described a soda-bearing monoclinic sanidine, 

which contains 4.92 per cent Na2 0 and 6.75 per cent K20. The cleavage angle (001) : (010) is 90° 01' and the extinction on (001) is parallel. 

The feldspar is monoclinic and consists approximately of equal parts 

of the isornorphous orthoclase and barbierite. In his paper Angel 

gives several references to earlier publications on feldspars which 

undoubtedly contain barbierite in isomorphous admixture.

This opportunity may be taken to call attention to an error in the 

first paper of Prof. Barbier referred to. The locality of one of the 

specimens is given as Francheville le Bas (Rhone). The correct 

locality is Orlienas (Rhone). Prof .Barbier asked me to call attention 

to this error in locality.

1 Angel, Franz, Ueber einen Natroasanidin von Mitrowitza: Neues Jahrb. fiir Min., Beil.-Band, vol. 

30,1910, p. 254.
CRYSTALLIZED TURQUOISE FROM VIRGINIA. 

INTRODUCTION.

A sample of a bright blue mineral, from near Lynch station, 

Campbell County, Va., was brought to the Geological Survey for 

identification by Mr. J. H. Watkins. As a few preliminary tests 

failed to identify the mineral with any known species, a complete 

study of it was undertaken. The results obtained show that the 

supposed new mineral is identical with turquoise. The chief interest, 

however, lies in the fact that this turquoise is well crystallized, so 

that it was possible to measure several of the minute crystals and 

determine thereby the crystallography of the mineral. I am deeply 

indebted to Mr. Watkins for his kindness in furnishing the material 

(now deposited in the United States National Museum, catalogue 

No. 86990), and in allowing this description to be published. A 

photograph of the specimen is shown in Plate I, A.

The matrix of the specimen consists of irregular fragments of glassy 

quartz of various sizes, cemented together by thin layers of turquoise 

crystals. On one side of the specimen the turquoise forms a drusy, 

botryoidal layer, cavernous in texture and including many small 

irregular fragments of the glassy quartz. The turquoise, with its 

many included quartz fragments, polishes well and makes a very 

handsome ornamental stone. The spheres which form the botryoidal 

surface bristle with minute crystals and average about 2 or 3 

millimeters in diameter. The individual crystals rarely are as much 

as a third of a millimeter long, being usually smaller and much 

thinner.

GENERAL DESCRIPTION.

The turquoise is blue in color and has a vitreous luster. Cleavage 

is present, possibly in two directions. The mineral is brittle and has 

a hardness of about 5, though the minute size and brittleness of the 

crystals make it difficult to determine the hardness with accuracy. 

The density, determined with a pycrometer on the powdered sample 

analyzed, is 2.816, which, when corrected for the 12.57 per cent 

insoluble material (mostly quartz) present, 1 gives for the pure turquoise the value 2.84.

1 See analysis, p. 45. 

42
U. S. GEOLOGICAL SURVEY BULLETIN 509 PLATE I

A. CRYSTALLIZED TURQUOISE FROM VIRGINIA, NATURAL SIZE. 

B. VARISCITE NODULE FROM UTAH, NATURAL SIZE. ON THE LEFT, AN AGGREGATE OF

CRYSTALS; ON THE RIGHT, THE ORDINARY COMPACT PHASE.

C. VARISCITE CRYSTALS IN A CAVITY OF AGGREGATE OF CRYSTALS, FROM UTAH. ENLARGED 6 DIAMETERS.
CRYSTALLIZED TURQUOISE FROM VIRGINIA. 43

Examined under the microscope, the crystals are clear and transparent and the material is very pure. Pleochroism is distinct, from 

colorless to pale bluish. Extinction is inclined on all sections, and, 

as verified by the measurements, the crystals are triclmic. None 

of the sections showed a good interference figure, though such as were 

seen indicated biaxiality. One cleavage plate, possibly parallel to 

M (iTO), showed extinction of 12° against the vertical direction and 

12° against the other edge (lIOAOTl ?). A different cleavage section of a rhombic shape showed extinction values of 5° and 34° 

respectively, but the orientation of this piece could not be determined. 

The double refraction of the mineral is high, about 0.04. The refractive indices are about: or = 1.61, f = 1.6'5. Lacroix 1 gives the value 

1.63 for the mean index.

CKYSTALLOGRAPHY.

The crystals are very minute and so closely grown together that it 

was almost impossible to obtain any suitable for measurement. One 

complete crystal was found that gave fairly good reflections, and the 

measurements made from it were verified by those obtained on a 

second less perfect crystal. A third incomplete one also yielded a 

 few measurements. The dimensions of the first two crystals were 

as follows:

Crystal No. 1, 0.27 mm. high (c axis), 0.32 mm. wide (b axis). 

Crystal No. 2, 0.32 ram. high (c axis), 0.40 mm. wide (6 axis), 0.12 mm. thick 

(a axis).

The crystals are triclinic and in angles very near to those of chalcosiderite. The angular values of turquoise and chalcosiderite are 

so close that the crystallographic elements of chalcosiderite have 

been adopted for those of turquoise, as the crystals of the latter 

rnineral are poorly adapted for accurate measurements. In fact, 

were it not for a knowledge of the crystallography of chalcosiderite 

(isomorplious with turquoise, as is shown in this paper in the discussion of chemical composition), it is doubtful if the orientation of 

the turquoise crystals could have been interpreted.

The values for turquoise are, then, as follows: a : I : c = 0.7910 : 

1 : 0.6051; « = 92° 58',/? = 93° 30', r = 107° 41'.

Forms: & {010}, a {100}, m {110}, M {iTO}, fc {Oil}.

The comparison of the measured angles with the calculated ones 2 

are shown below.

1 Lacroix, A., Mineralogie de la France, vol. 4, 1910, p. 529.

2 These calculated values are, with one exception, taken from the values calculated forchalcosiderite 

by Maskelyue, Jour. Chem. Soc., vol. 28, 1875, p. 58(i.
44 MINEBALOGICAL NOTES SEBIES 2. 

Comparison of measures and calculated angles, turquoise.

Angle.

HOAioo...............................

IOOAHO.............................. noAiio...................... :.......

110 AGIO a............. .................. oiiAlio................. ...... '.......

011A100..............................

OllAHO................. .............

OllAOlOa... ..............:............

Crystal 

No. 1.

0 /

45 12

31 14

104 14

37 28

107 42

Measured.

Crystal 

No. 2.

0 /

31 28

38 39

105 15

95 33

110 00

117 26

Crystal 

No. 3.

0 /

31 25

104 03

Calculated.

0 /

44 50

31 10

104 00

40 54

105 36

95 45

109 36

119 19

M

a The faces of {010} gave very poor reflections.

The habit of the crystals is shown in figure 2.

The forms a {100} and M {iTO} are large and striated vertically,

a generally more striated than M. 

The prism m {110} is small sized 

and striated parallel to the edge 

(110): (Oil). Between m and Tc 

{011} lies an undetermined small 

face very much striated. The 

clinopinacoid & {010} is very small 

and uneven and gives a very poor 

reflection. The dome fc {011} is 

the only terminal face definitely 

determined and is strongly striateft 

on crystal No. 1, though perfectly 

smooth and yielding an excellent 

reflection on crystal No. 2. It may 

be that the face Jc on crystal No. 2 

is a cleavage face, as an easy cleavage parallel to this dome was noted 

by Maskelyne on chalcosiderite.

The pointed appearance of the 

minute crystals is due to the sharpness of the upper right-hand corner 

where the intersection of #{100} 

and fc{OTl} yields an acute point.

CHEMICAL COMPOSITION.

Abundant material was available for the analysis, which was 

made on carefully selected pieces free from all impurities except the 

quartz. It was found that the mineral is insoluble in boiling hydroFIGURE 2. Turquoise crystal / 

&{010},a{100},m<110},
CRYSTALLIZED TURQUOISE PROM VIRGINIA. 45

chloric acid, but that after gentle ignition (when it has turned brown) 

it is readily soluble in acids. The mineral does not lose any water 

below 200° and retains its blue color at that temperature. Between 

200° and 650°, all the water is given off 1 and the mineral becomes 

greenish in color. On higher heating the greenish color changes to a 

brown. The mineral is infusible before the blowpipe, but becomes 

brown.

The average analysis is shown in the table below in the first column; in the second column is given the same analysis with the 

insoluble matter (quartz) deducted.

Analysis and ratios of turquoise.

P O

A12 03 ...............................

 Fe-jOs-... ............................

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

H20................................

Insoluble matter. .....................

Analysis.

29.84

31.91

.18

7.87

17.59

12.57

99.96

Analysis 

(insoluble 

matter 

deducted).

34.13

36.50

.21

9.00

20.12

99.96

Ri

0.240

.357

.001

1.118

itio.

2. 07 or 2

3. 09 or 3

07 nr i

9. 64 or 9

The formula derived from the ratios of the analysis is Cu0.3Al2 03 .- 

2P205 .9H2O. According to Penfield's suggestion 2 as to the relation 

of the hydroxyl groups, this formula can be interpreted as 

CuOH.6[Al(OH) 2].H5 .(P04 ) 4 . I believe that this formula expresses 

the definite composition of turquoise and a comparison with other 

analyses shows that this formula is doubtless the correct one.

Among the best analyses of turquoise is that made by Penfield 2 

on material from Lincoln County, Nev. This turquoise was "of 

exceptionally fine quality * * * very fine-grained, of a beautiful robin's-egg blue color, and broke with a smooth fracture * * * 

when examined under the microscope, the turquoise seemed to be 

perfectly uniform, showing no evidence of being made up of two 

substances * * * it acted somewhat on polarized light." Its 

density is given as 2.791.

In the following table are given the analysis of the turquoise from 

Virginia and Penfield's analyses of turquoise from Lincoln County, 

Nev. In the third column is shown the composition calculated for 

the formula proposed.

1 Nearly all the water is expelled below 400°.

2 Penfleld, S. L., On the chemical composition of turquoise: Am. Jour. Sci., 4th ser., vol. 10,1900, p. 346.
46 MINERALOGICAL NOTES SERIES 2. 

Analyses of turquoise.

,

p r2r> u5 . ...................................

A 1 f)

Fe,03 -----------------------------------

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

H20... .............................:....

Insoluble matter. ........................

Virginia.

34.13

36.50

.21

9.00

20.12

99.96

Nevada.

34.18

35.03

1.44

8.57

19.38

.93

99.53

Calculated for 

Cu0.3Al203 .- 

2P205 .9H20.

34. 12

36.84

9.57

19.47

100. 00

The agreement of the three analyses is very close, so that the 

formula Cu0.3Al203 .2P205 .9H20 expresses definitely the composition of this mineral.

Of the other analyses of turquoise, in which the purity of material 

is not so definitely known as in the two, analyses just cited, only those 

given by Penfield * are quoted an the following table:

Analyses of turquoise.

PAAI n

Fe203 - ------

CuO........

H20.........

Sp.gr.......

Calculated.

34.12 

36.84

9.57 

19.47

100. 00

Persia. 

(Church.)

32.86 

40.19 

« 2. 45 

5.27 

19.34 

60.36

100. 47 

2.75

Russia. 

(Nicolajew.)

34.42 

[35. 79] 

3.52 

7.67 

18.60

100. 00 

2.89

California. 

(Moore.)

33.21 

35. 98 

2.99 

7.80 

19.98

99.96 

2.86

New Mexico. 

(Clarke.)

31.96 

 '39. 53

6.30 

19.80 

<*1. 28

98.87

32.86 

36.88 

2.40 

7.51 

19.60 

eO. 54

99.79 

2.80

28.63 

37.88 

4.07 

6.56 

18.49 

/4.20

99.83

o Given as FeO. The figures are in better agreement with values calculated from formula if the iron is 

considered in the ferrous condition. 

6MnO.

c Includes some Fe2Q3 . 

d Insoluble, 1.15; CaO, 0.13. 

e Insoluble, 0.16; CaO, 0.38. 

/Insoluble.

The high alumina values may be partly accounted for by the 

admixture of a little aluminous rock. By considering some of the 

iron present as ferrous oxide, FeO, isomorphously replacing the 

CuO, the analyses agree very well with the values calculated for the 

composition.

Penfield's idea that the composition of the mineral should be 

expressed as [A1(OH) 2 , Fe(OH) 2 , CuOH, H]3PO4 can be more defi1 Loc. cit.
CRYSTALLIZED TUEQUOISE FROM VIRGINIA. 47

nitely fixed now, for the analysis of crystals of turquoise shows that 

the A1(OH) 2 , CuOH, and H are present in fixed amounts, namely, 

in the proportions 6: 1: 5. Penfield's analysis agrees very closely 

with these figures. 1

Crystallographic measurements have shown the apparent isomorphism of turquoise and chalcosiderite. The formula given for 

chalcosiderite is Cu0.3Fe203 .2P205 .8H2 0, which differs from that 

proposed for turquoise only in containing one molecule less of water. 

From Maskelyne's 2 description of the material used for the analysis 

of chalcosiderite it seems probable that the sample was contaminated by a little andrewsite, limonite, and dufrenite, all of which 

contain less water 3 than chalcosiderite, so that the value he obtained is probably a little low.. The correct formula for chalcosiderite should probably be written with 9H2O instead of 8H20, in 

which event the isomorphous character of this mineral with tur-- 

quoise will be clearly brought out.

Turquoise..........Cu0.3Al203 .2P205 .9H20, triclinic.

Chalcosiderite..... .Cu0.3Fe2Q3 .2P205 .9H20, triclinic.

SUMMARY.

In closing, the three main points developed in this paper may be 

briefly restated:

1. Turquoise is triclinic with the crystal form determined.

2. Turquoise has the definite composition Cu0.3Al2 03 .2P2 05 .9H2 0.

3. Turquoise and chalcosiderite are isomorphous.

i Penfield deduced the ratios 7:1:6 from his analyses, but 6:1:5 is still closer. 

"Maskelyne, N. S., On andrewsite and chalcosiderite: Jour. Chem. Soc., vol. 28,1875, p. 586. 

B Andrewsite has 8.8 per cent, limonite 14.5 per cent, and dufrenite 10.5 per cent water; chalcosiderite 

has 15 per cent.
CKYSTALLIZED VARISCITE FROM UTAH. 

INTRODUCTION.

The material on which the following descriptions are based was 

collected near Lucin, Utah, by Mr. Douglas B. Sterrett, of the United 

States Geological Survey. A part of the material consists of welldeveloped crystals, a form of occurrence so unusual for var-iscite that 

the identity of that mineral was not discovered until after detailed 

study. The quantity of material was sufficient to determine all the 

chief properties of the mineral, one of the. most striking of which was 

brought out by Mr. Sterrett in heating a fragment of'it before the 

blowpipe, for at a low temperature its vivid green color was changed 

readily to a deep lavender. The chemical study of the mineral was 

extended in order to find out if possible the cause of this change. 

The various properties of the lavender-colored variscite were studied, 

as well as those of the green mineral, in order to discover their relations. I wish to express my thanks to Mr. Sterrett for permission 

to describe this very interesting mineral and for his generosity in 

furnishing the material needed.

OCCURRENCE AND GEM QUALITY.

The following notes on the occurrence of the variscite near Lucin, 

Utah, and of the kind and quality of the gem stones procured are by 

Sterrett: 1

The variscite deposits, 5 miles northwest of Lucin, Utah, * * * are in the 

northern part of an irregularly shaped hill, called Utahlite Hill. Utahlite Hill is 

about 1 mile long in a northwest-southeast direction and about one-half mile wide. 

It has an elevation of about 5,000 feet above sea level and rises over 300 feet above 

the mesas and gentle slopes at its base, and about 500 feet above the railroad at Lucin. 

Four claims have been located and these are, in order from northwest to southeast, 

Utah Gem, Greenback Lode, Utahlite, and Protection Lode. * * *

[The variscite deposits are] in and around small rocky summits standing above the 

rest of the hill. These summits have cavities and small caverns [in them] * * * 

resembling those made by wave action. They were probably formed on one of the 

shore lines of the former Lake Bonneville. The work done at the time of examination consisted of an open cut 50 feet long and 2 to 5 feet deep with several prospect 

pits.'

1 Gems and precious stones: Mineral resources U. S. for 1910, U. S. Geol. Survey, 1912, pp. 894-896. 

48
CRYSTALLIZED VARISCITE FROM UTAH. 49

The rock in which the variscite occurs and which forms the crest of the hill is 

cherty or chalcedonic quartz, which contains inclusions of nodules and streaks of 

limestone. The limestone inclusions range up to a foot thick and in places are several 

feet long. The character of most of the rock is that of a hard breccia cemented 

together by silica. This breccia forms rough, rocky ledges and knobs rising from a 

few feet to 25 feet above the hill slopes. * * * Three of these knobs contain large 

quantities of variscite.

The variscite occurs in balls, nodules, and irregular masses in the chert. Veins of 

variscite are not common, but some with a northeast strike and northwest dip were 

seen. The nodules and balls of variscite range in size from a fraction of an inch to 

several inches across, and some of the segregations of variscite inclosing matrix are a 

foot across. The variscite fills fractured and brecciated zones in the rock, some of 

which it replaces, and it incloses other parts. The replacements are generally rounded, 

concretionary masses, often with banded concentric structure. The fragments of 

some of the brecciated rock, especially white quartz, that have been inclosed by and 

cemented with variscite, have remained angular and sharp. Some of the concretionary forms appear to grade from green variscite cores into the inclosing yellow, 

brown, gray, and white phosphatic and cherty minerals. There is considerable 

chalky mineral filling cavities in the variscite-bearing rock and coating the nodules 

and masses of variscite. A quantity of variscite pebbles and cobbles have been 

found in the cut in the loose detritus below the main outcrop on the Utahlite claim. 

These probably owe a large part of their rounded form to the nodular shape of the 

variscite in the original rock, but have also probably been rounded by water action 

on a former lake shore. The pebbles are coated with a white chalky substance, and 

have to be broken into before the presence or quality of the variscite can be determined.

* * * Both the variscite and the matrix minerals possess various shades of color, 

several of which are sometimes present in a single specimen. The different colors 

combined with the various markings and patterns due to the structure of the mineral 

and brecciation of the matrix furnish a large range in the types of stones that can be 

cut from the variscite. The variscite ranges in color, from a very pale green through 

different shades of green to bright grass green. The matrix varies from white to gray, 

to yellow, to brown, and nearly to black.

The gems that can be cut from the variscite from the Edison and Bird mines range 

from large pure stones with light to dark green color through those with small quantities of matrix, to those in which the matrix predominates. The dark and bright green 

variscite is obtained in pieces that will cut into pure stones measuring more than 

an inch across, and paler-colored mineral will yield even larger pure stones. Some of 

the bright-green variscite is partly translucent, and thin pieces and small pebbles display then- color well in the partially transmitted light. This is especially true of the 

coarser-grained, finely crystalline variscite. Specimens of matrix are obtained that 

will yield slabs 6 inches across, some of wjiich show quite remarkable patterns and 

colors. One block of matrix found at this mine measures 4 to 6 inches in diameter and 

weighs several pounds. The whole mass is composed of variscite mottled with brown 

and white matrix. The pattern is the typical turtle-back, and the markings are coarser 

in some parts of the specimen than in others. The markings are due to rounded 

patches or nodules of pale to bright-green variscite, some of which are surrounded by 

rims of white or gray, and all filled in with purplish brown matrix. The brown matrix 

occurs only as an internodular filling, and the seams are rarely over a millimeter thick. 

Occasional larger patches of matrix occur where several seams meet around the variscits 

nodules. The rounded masses of variscite vary from a fraction of a millimeter to a 

centimeter in diameter. Other smaller pieces of mottled variscite have been found 

23590° Bull. 509 12 4
50 MINERALOGICAL NOTES SERIES 2.

along with, specimens of brown, gray, and white matrix, with practically the same texture. Some pieces of mottled matrix contain little if any variscite, but would itself 

cut into stones with the turtle-back markings.

Among other types of variscite matrix is that with bright grass-green variscite mottled with patches and cloud-like masses of lighter green material, or vice versa. Such 

matrix may contain seams and spots of white, gray, or yellowish mineral through it. 

A white quartz breccia cemented and filled in with bright green variscite is also a 

pleasing stone when cut, but is more difficult to polish because of the difference in 

hardness of the two minerals. The quartz occurs in sharp angular fragments, which 

are in excess of the variscite in some specimens, but generally less prominent.

The variscite and variscite matrix from this locality would yield'very beautiful gems 

for the so-called barbaric jewelry. It is susceptible to nearly every form of cutting 

used with opaque gems, but on account of its comparative softness is not adapted 

to rough wear. For necklaces, pendants, brooches, pins,, belt stones, etc., it is well 

suited. The especially bright colors of some of the variscite from this locality are 

rarely found in that from other places, and the variety of markings shown by the 

matrix is probably equal to any other material found.

GENERAL DESCRIPTION.

The material available for study consists of nodular aggregates of 

variscite, irregular in shape and of various dimensions. The deep 

green aggregates of crystallized mineral consist of tabular crystals, a 

few of which reach a millimeter in length. Their breadth is about 

half their length, and their thickness varies from about one-fourth 

of a millimeter to very thin plates. The coarser aggregates of variscite 

consist of well-developed crystals (PL I, B, C, p. 42), which are often 

nearly complete. The finer-grained material does not show such distinct crystals, and the very fine-grained compact mineral 'has more 

the appearance of a cryptocrystalline mass. Several small cavities 

in the coarse material were lined with projecting crystals which furnished good material for crystallographic study. The crystals are 

transparent and pale green when viewed under the microscope. A 

view of such a cavity enlarged six times is shown in Plate I, C.

OPTICAL PROPERTIES.

ORIENTATION AND PLEOCHBOISM.

The crystallographic orient atiori was so chosen that the large, flat 

face of the crystals became the brachypinacoid 6 {010} and the striations on this face were placed vertically. Variscite being orthorhombic, these facts are sufficient to definitely orient the crystals so that 

the optical relations can be readily comprehended. The basal pinacoid, c {001}, was not observed on these crystals, and the macropinacoid, a { 100}, is a rare form, seldom larger than a narrow face between 

the unit prisms m and m"'.

The optical relations were ascertained by studying the flat crystals 

and by means of two thin sections of the granular aggregate, which
CRYSTALLIZED VARISCITE FROM UTAH. 51

were carefully prepared without being subjected to any heat. If a 

section of the granular variscite be made in the ordinary manner, the 

heat employed in the operation is sufficient to change the green color 

of the mineral to deep lavender, with consequent changes in the various physical properties.

The extinction is parallel in all sections, and the mineral behaves 

optically in strict concordance with the orthorhombic symmetry of 

the crystals. The axial plane is parallel to the flat face & {010}, and 

the acute bisectrix is normal to the base c {001}, the obtuse bisectrix 

then being normal to a {100}. The mineral is positive, so that the 

acute bisectrix, identical in direction with the crystallographic% axis c, 

is the axis of minimum velocity of light. The optical relationship can 

therefore be expressed in the conventional form as follows:

c= Z =c

The axial angle is large; 2E was measured as about 113°. Dispersion was not marked, and its kind could not be determined.

Viewed in transmitted light under the microscope, the crystals are 

colorless if very thin, or pale green if somewhat thicker. The coloring pigment is not uniformly distributed, but is generally arranged 

in irregular cloudlike areas. In a few slides the coloring seemed to 

be distributed in some relation to the shape of the crystals and was 

most intense near their edges.

The pleochroism is distinct, but slight. Its relation to the crystal 

directions is shown in the following scheme :

a (X) = colorless. 

& (Y)= pale green. 

c (Z) =pale green.

The weakness of the pleochroism is in striking contrast to that of 

the heated lavender-colored material in which, as is described on 

page 53, the pleochroism is strong.

REFRACTIVE INDICES.

The indices of refraction were measured by the method of oil 

immersion for f and a. The values found are: 7- =1.577 and <* = 

1.547. Therefore f <* = 0.030, which. is very close to the average 

value (0.032) found by actual determination of the birefringence. 

This birefringence was measured accurately on the flat brachypinacoid, and the average value obtained is 0.032. The value was 

measured on 1 1 crystals, with the following results :
52 MINERALOGICAL NOTES SERIES 2. 

Birefringence (r a) measured on b {010}.

Crystal

No.

1

2

3

4

5

6

7

8

9

10

11

Average.

Thickness in

millimeters.

0.055

.044

.042

.070

.051

.051

.066

.055

.042

.053

.047

Birefringence.

0.034 "

.029

.035

.027

.031

.037

.029

.034

.030

.030

.034

.032

As the value 0.032 is, of course, more accurate than the value 

0.030 obtained by measuring the indices directly, the values of 

and a are each changed one unit so as to bring their difference in 

accord with the more accurately determined value of the birefruv 

gence, and are therefore taken as 1.578 and 1.546, respectively.

The value for 0 was found by measuring the difference of refraction (0 or) in basal sections of the mineral. A thin section of the 

crystalline aggregates furnished basal and macropinacoid sections of 

the same thickness, so that the value (/?-«) could be determined 

by noting the interference colors (first order blue) on the basal sections and comparing them with the colors on sections showing the 

maximum birefringence. The value (/? <*) was thus found to be 

0.010. Therefore 0=1.556.

A section of a crystal that seemed to be nearly parallel to a{100} 

showed a very large axial angle and a difference of refraction of 

about 0.020, which, for a section parallel to a{100}, should be 

0.022.

A summary of the optical properties as determined follows:

Axial plane 6 (010). Bxa JL c (001). Positive. 

a= 1.546,- 0=1.556, 7-= 1.578.

- 0 = 0.022, 0 « = 0.010.

- 1.560.

STRUCTURE OF CRYSTALS.

 An additional feature of considerable interest is the structure of 

the crystals. Although the material is well crystallized and the 

individual crystals sharply bounded by plane and brilliant surfaces,
CRYSTALLIZED VABISCITE FROM UTAH. 53

the interior of the crystals is, in most cases, crowded with a mass 

of small particles irregularly bounded and not in parallel position 

with the crystal itself. In some crystals these particles are absent; 

in others they are sparsely scattered. Still other crystals contain a 

vast number of these particles, generally closely aggregated. These 

aggregates are either irregular in shape and occupy the center of 

the crystal, or else they are so arranged as to correspond with the 

shape of the crystal itself. Such a regular grouping of these particles is shown in figure 3, which illustrates also the tabular habit 

of the variscite crystals. In figure 3 the brachypinacoid &{010} is 

drawn in front in order to show better the mode of distribution of 

the particles. These particles are in general irregular in shape, 

though occasionally a rectangular one can be noted in the mass. 

The particles still manifest themselves in the dehydrated lavender 

crystals and show no difference, except in their 

orientation and shape, from the rest of the crystal.

PROPERTIES OF DEHYDRATED LAVENDER 

VARISCITE.

The very remarkable color change undergone 

by the mineral on dehydration at a relatively 

low temperature (below 160°) has a marked 

effect on its optical properties. The most striking change is in the pleochroism. The green 

crystals of variscite are only faintly pleochroic 

(colorless to pale green), whereas the lavender 

ones are strongly pleochroic with intense colors.

The optical orientation of these lavendercolored crystals could not be determined, though 

numerous attempts were made, both on loose crystals and on thin sections of the granular aggregate. 

The birefringence of the mineral has become so 

low that no definite results could be obtained when tests for axial 

angles were made. Both basal and brachypinacoidal sections seemed 

to show the emergence of a bisectrix with a very large axial angle, 

though, as stated, the results were inconclusive. It could, however, 

be easily seen that the optical orientation was changed. In the green 

crystals, viewed on the flat f ace b{ 010}, the vertical axis is a direction 

of minimum velocity, but on the lavender crystals this same direction is 

one of maximum velocity. Similarly, on basal sections the axis & is a 

direction of minimum velocity for the green crystals, whereas on the 

lavender ones the & axis is a direction of maximum velocity

The pleochroism of the lavender crystals is strong and very striking. 

All the colors are combinations of red and blue and are therefore 

rather hard to describe accurately. On crystals that are not too thin

FIGURE 3. Variscite crystal, 

showing regular grouping of 

small particles. 6 {010}, m 

{110},e{012>. The brachypinacoid b {010> is drawn in 

ront.
54 MINERALOGICAL NOTES SERIES 2.

the colors are very intense and beautiful. The brachypinacoidal 

sections are strongly pleochroic, whereas basal sections hardly show 

any difference in shade in different directions. The colors observed 

may be described as follows:

a axis = lavender.

& axis = pinkish lavender.

c axis = violet.

The color effects given above are such .as were noted on crystals 

that had been heated above 160° gradually. If the green crystals be 

suddenly heated to a high temperature, as, for instance, by putting 

them on a piece of platinum foil and suddenly heating them in the hot 

flame of a Bunsen burner, the results are different. The crystals are 

then considerably cracked, and on brachypinacoidal sections the 

optical orientation is like that of the green crystals that is, the c axis 

of the crystal corresponds to a direction of minimum velocity. Moreover the pleochroism is interchanged so that 

a axis = violet. 

c axis = lavender.

The changes in the indices of refraction and the birefringence undergone by the green variscite crystals on changing to the lavender phase 

are also very marked. The mean refractive index drops from 1.560 to 

about 1.448 and the birefringence from 0.032 to 0.003 or even less. 

The birefringence does not exceed 0.003 in any section and is much 

less in most. The approximate values of the indices are as follows:

« = 1.447,0= 1.448, r = 1-450; f -a = 0.003.

This decrease in the values of the refractive indices and the birefringence is accompanied by loss of water. It is a fact worth emphasizing that the loss of water, without destroying the optical possibilities of the mineral, decreases both these values.

When the lavender crystals are heated with water on the steam 

bath (not over 100°) for several days, they gradually lose their 

lavender color and become a dirty grayish-white. In this condition 

they are nonpleochroic. A sample treated in this way for about a 

week was then air-dried for several days, and the loss on ignition 

(water absorbed) determined. This amount was found to be 2.05 

per cent. The ignited crystals again became deep lavender in color. 

It therefore seemed that it might be possible by appropriate treatment to change the dehydrated lavender crystals back to their original 

vivid green color. With this in mind, some of the lavender crystals 

-were treated with hot water for several days until they became 

grayish-white in color, and then sealed in a glass bomb with a little 

water and heated for several hours at a higher temperature. The
CRYSTALLIZED .VARISCITE PROM UTAH. 55

glass bomb was first heated for about four hours at 170°, the next day 

for the same time at 190°, and the third day for the same time at 225°. 

Unfortunately, it was not possible to heat the tube at these temperatures continuously, as should probably have been done. After three 

days' heating, as just described, the grayish-white crystals had 

become a very pale greenish-yellow, but when the crystals were 

removed from the tube and the loss on ignition determined after airdrying extending over several days, the result was disappointing. A 

loss of only 1.12 per cent was found, so that the crystals had absorbed 

less water in the glass bomb treatment than by simply treating with 

hot water.

The crystals from the glass bomb were very light brown or nearly 

colorless when viewed under the microscope. Pleochroism was 

distinct, though very slight. Parallel to the c axis, a direction of 

maximum velocity (unlike the green crystals), light brown; parallel 

to the a axis, a light brown with a decided greenish-yellow vint. The 

birefringence is about 0.006, the interference colors on the thicker 

crystals reaching into first order yellow. The areas of " Irregular 

aggregates" (shown in fig. 3) are more strongly colored and are 

indefinite in character. They somewhat resemble the kaolinization 

effects seen in rock slides.

RELATION TO ANALOGOUS MINERALS.

A brief comparison of the optical properties of variscite, as given, 

with those of the analogous minerals scorodite, strengite, and phosphosiderite, shows some close relationships as well as some marked 

differences.

The optical properties of variscite given by Lacroix 1 are not 

entirely in accord with those given in this paper, but this disagreement 

is due to the fact that Lacroix's material consisted of fibrous material 

and not of distinct crystals. He gives the axial plane as parallel to 

I {010}, with negative acute bisectrix normal to a {100}, whereas 

the acute positive bisectrix is normal to c {001}. The value of 2E is 

given as about 96° and the mean index as 1.579, which is a little 

higher than the value 1.560 found on the Utah crystals, but almost 

identical with the maximum index found on them, namely (7-), 1.578. 

The birefringence is stated to be a little higher than that of quartz, 

but the birefringence observed by Lacroix was probably not the 

maximum, which reached a value of 0.032 in the crystals from Utah.

Comparison of the chief optical properties of the different analogous minerals can be made most conveniently if they are shown in 

tabular form. The orientation of the variscite is so chosen that 

the axial phase is 6(010), but it is possible, as shown in the following

1 Lacroix, A., Minfiralogie cle la France, vol. 4,1910, p. 479.
56 MINEEALOGICAL NOTES SEBIES 2.

pages of this paper, to orient the crystals so that the axial plane is 

a (100), analogous to that of scorodite and strengite.

Comparison of optical relations.

Mineral.

Strengite... ..........

Axial 

plane.

6(010)

a(100)

a(100)

6(010)

Optical 

sign.

+

+

+

+

Bxa.

1(001)

1(001)

1(001)

1(001)

2E.

o

113

130

60

126

Mean 

index.

1.560

1.825

1.73

Birefringence.

0.03

.03

.03

In adopting the orientation for variscite as given in this paper, 

with the optic axial plane parallel to 6(010), an interesting condition 

obtains for the isomorphous mixtures of variscite (A1P04 .2H20) and 

strengite (FePO4 .2H20), for in the latter mineral the optic axial 

plane is parallel to a(100). Such an isomorphous mixture is represented by the mineral barrandite, of which two analyses are on record 

and in both of which the iron phosphate predominates, so that 

barrandite, instead of being a distinct mineral species, is in reality 

only an aluminous strengite.1 In strengite the axial plane is a(100) 

and 2E equals 60°, whereas in variscite the axial plane is 6 (010) and 

2E is nearly twice as large. The isomorphous admixture of a small 

amount of variscite in strengite would therefore tend to decrease the 

axial angle of strengite, and with a certain amount of variscite, the 

axial angle would become zero. A still greater amount of variscite 

in the mixture will give an increasing .axial angle, but with the axial 

plane now parallel to 6(010) as in pure variscite. Since the axial 

angle of strengite is much smaller than that of variscite, an isomorphous mixture with an axial angle of about zero should contain 

more strengite than variscite.2 Both analyses of barrandite show 

an excess of the strengite molecule, the ratio in the first being 4:3 

and in the second 5:2. In the analysis giving the last ratio, it is 

therefore highly significant to note that Lacroix in describing 3 barrandite states that the optic axes are very close, so that the value of 

2E is very small. In the analysis of barrandite given by Lacroix the 

ratio of Fe203 to A12 03 is about as 5:2. An approximate calculation 

of the value of the axial angle of such an isomorphous mixture shows 

that it should be very small, approximately 10°.

1 Compare p. 38.

s It is interesting to note that should an isomorphous mixture of variscite and strengite be found (without definite crystals) in such proportions that the axial angle is zero; the discoverer would be very likely 

to consider the find as a distinct new species, as it would be strictly uniaxial, whereas both variscite and 

strengite are biaxial.

s Lacroix, A., Min<Jralogie de la France, vol. 4,1910, p. 486.
CEYSTALLIZED VABISCITE FKOM UTAH. 57

On the other hand, it must be stated that the density and mean 

refractive index of barrandite, as given by Lacroix, are not consistent 

with the values calculated from those of variscite and strengite, as 

the following table shows:

Comparison of values for barrandite.

Variscite ....................................................

Density.

2.54

2.87

2.59

2.78

Mean 

refractive 

index .

1.560

1. 825

1. 575

1.749

a Barrandite consists of 5 parts strengite and 2 parts variscite.

The wide discrepancies in the found and calculated values of the 

density and refractive index, respectively, are not in accord with 

the idea of the isomorphous character of barrandite as developed for 

the optical properties.

CRYSTALLOGRAPHY.

INTRODUCTION.

The flat crystals are orthorhombic in their symmetry and simple 

in their combination. The large face is taken as the brachypinacoid, 

and the chief forms noted, as shown in figure 4, are: 6(010), 

m(110), and e(012). In addition to these forms the macropinacoid 

a(100) is sometimes present as a narrow face. Occasionally the 

crystals are much longer and the prism faces more developed in 

comparison with the brachypinacoid. The common habit of the 

crystals is shown in figure 4. A better idea of the shape of the crystals 

can be had from figure 3, on page 53, which shows a variscite crystal 

so drawn as to bring the brachypinacoid &(010) in front. The 

rectangular tabular shape of the crystals, due to the large development 

of the brachypinacoid, is well illustrated in the same figure.

Several other forms are present on these crystals, but they could 

not be determined. On crushing some of the coarsely crystallized 

aggregate and examining it under the microscope one occasionally 

sees an acutely-terminated crystal which has the corners replaced by 

small faces, probably those of the unit pyramid.

In orienting the crystals of variscite three positions are available, 

depending on the pinacoid to which the broad face is referred. This 

broad face is generally slightly striated vertically. In conformity 

with the analogous mineral scorodite, the striations are taken as
58 MINEKALOGICAL NOTES SERIES 2.

parallel to the c axis. Striated crystals of scorodite have been 

described by. several authors. Kokscharow 1 states that the form {010} 

is strongly striated vertically. Zimanyi 2 describes scorodite crystals 

on which the prism d {120} is vertically striated and Lacroix 3 mentions vertical striations on {120} and the two pinacoids {100} and 

{010}.

The crystals of variscite have been so oriented that the broad face 

is ~b {010}, as already described and illustrated in ngure 3. Lacroix 4 

mentions scorodite crystals slightly flattened parallel 

either to a {100} or to 6 {010}. He also states that 

a rare phase of strengite is formed by plates flattened parallel to a {100}.

The possibilities of the three available orientations will be discussed after the measurements of 

the variscite crystals are given.

CALCULATION OF ELEMENTS.

Variscite being orthorhombic, only two angular 

values are necessary for a determination of the crystallographic elements.

The fundamental values of variscite are:

6Am =(010) : (110) =48° 10' 

I'Ae =(010) : (012) =61° 17' 

From these values the axial ratio is found to be: 

a : I : c = 0.8952 : 1 : 1.0957.

The measurements from which the fundamental 

values for variscite were obtained are as follows: 

In the measurements of the angle (010) : (110) it is 

possible-to obtain eight values on each crystal, 

namely _(010 : 110), (010 : TlO), (010 : llQ), 

(010 : HO), £(110 i IlO)LJ(lIO : 110), 90°- 

HllO : 110),- 90°-i(110 : TTO). In the following 

table, of these possible eight values, only those are 

given where the reflections from the faces were 

fairly good and distinct. The numbers at the heads

of the columns refer to individual crystals, and the averages of the

various measurements are given below.

1 Kokscharow, N., Mineralogie Russlands, vol. 6,1870, p. 309.

2 Zimanyi, K., Beitrage zur Mineralogie der Komitate Gorr.or und Abanj-Torna: Fold. Kozl., vol 35, 

1905,p. 545.

s Lacroix, A., Mineralogie de la France, vol. 4,1910, p. 472. 

4 Idem, p. 474.

Tit

FIGURE 4 . Variscite 

crystal,6(010),TO(110) 

c(012).
CRYSTALLIZED VARISCITE FROM UTAH. 

Measurements of angle b/\m=(010) : (110}.

59

1

0 /

48 28 

47 34 

48 42

47 21

47 55

48 08'

48 01

2

0

0 /

48 26 

48 11 

48 33

47 51

48 18

48 14

48 14

4

0 /

48 19 

48 44 

47 56

48 22

48 10

48 18

5

0 /

48 02 

48 13

48 08

6

0 /

48 07 

48 12 

48 14

48 19

48 13

7

0 /

46 59 

49 07

48 04

48 03

Average of 26 measurements=48° 10/ .

For the faces of e {012} the number of possible measurements was 

not so large,, because the crystals measured were broken off at the 

lower end.

Measurements of angle b/\e=(010) : (012).

Crystal

Crystal

Crystal 

Crystal

No.

No.

No. 

No.

2..

3..

4.. 

5..

0

(61 '161

/61 161

. 61 

61

,

21 

15

22 

08

28 

19

Crystal No. 6...

Crystal No. 7...

Crystal No. 8...

o

(61 

161

(61 

161

(61 

161

,

31 

10

26 

10

14 

01

Average of 12 measurements=61° 17'.

The only crystallographic study hitherto made of variscite is the 

work of Chester 1 on the Arkansas mineral. He found some minute 

crystals with the forms 6 ,{010}, a {100}, m {110}, and c {001}. _0f 

these, I, m, and c were well developed. The angle m Am'" (110 : iTO) 

is given as 65° 54', but it has not been possible to correlate this angle 

with any simple form for the variscite-scorodite group.

The follpwing table gives the coordinate angles for the forms of 

variscite. The table is adapted for measuring the crystals by the twocircle method, but, of course, it also gives the necessary interfacial

angles.

Forms and coordinate angles for variscite.

[a=0.8952, c=1.0957, p0=1.2240, g0=1.0957.]

No.

1 ................................

2

3................................

4. ...............................

Letter.

b 

a 

m 

e

Symbol.

Gdt.

0 00 

000

000*

Miller.

010 

100 

110 

012

0

0 /

0 00 

90 00 

48 10 

0 00

P

o /

90 00 

90 00 

90 00 

28 43

1 Chester, A. H., Note on the crystallization of variscite: Am. Jour. Sci., 3d ser., vol. 15,1878, p. 207.
60 MINERALOGICAL NOTES SERIES 2.

The three possible orientations for the variscite crystals will now be 

given and their relation to the orientation of the analogous minerals 

scorodite, strengite, and phosphosiderite studied.

FIRST ORIENTATION.

The first orientation is the one chosen for the mineral, as it best 

shows the relation of variscite to the other minerals and at the same 

time yields the simplest indices for the crystal forms of variscite. In 

the comparisons two orientations are given for phosphosiderite, both 

of which are different from the accepted position of that mineral. 

The first one, given as phosphosiderite (1) in the following tables, is 

the one suggested by Bruhns and Busz; l and the second one, phosphosiderite (2) is obtained by interchanging the a and c axes in the 

generally adopted position and then doubling the new a axis.

The close relation between the angles of variscite ancl the other 

minerals of analogous composition is shown in the table below:

Comparison of angles (first orientation).

Angle.

6/\m=(010) :(110)............

6/\c=(010) : (012).. ;.........

Variscite.

i

0 /

48 10 

61 17

Scorodite.

o /

49 07 

64 30

Strengite.

0 /

49 08 

- 63 50

Phosphosiderite .

1

0 /

50. 33 

64 52

2

0 /

48 45 

61 57

A comparison of the axial ratio also shows clearly the similarity 

in values and the very close agreement of variscite with phosphosiderite (2). A greater difference is shown by comparison with the 

values of the other minerals.

Comparison of axial ratios (first orientation).

Mineral.

Variscite ..................................................

Phosphosiderite (2) .........................................

a axis.

0. 8658

.8652

.8952

.8229

.8772

c axis.

0. 9541

.9827

1. 0957

.9381

1. 0660

It is worthy of special notice that the agreement of values is much 

closer for variscite and phosphosiderite (2) than it is for either 

variscite and scorodite or strengite. This fact led to the suggestion

1 Zeitschr. Kryst. Min., vol. 17,1890, p. 555. Also given in Dana's System of mineralogy, 6th cd., 1892. 

p. 823.
CRYSTALLIZED VABISCITE FKOM UTAH. 61

that perhaps the mineral here described was not variscite but a new 

mineral bearing the same relation to true variscite that phosphosiderite is supposed to bear to strengite. The analysis, however, 

shows that the crystallized variscite from Utah agrees well with the 

formula A12O3 .P2 05 .4H2O. A careful study of the relations of phosphosiderite to strengite, considered with the close crystallographic 

values of phosphosiclerite and variscite, leads to the conclusion that 

phosphosiderite and strengite are identical, notwithstanding the 

apparent differences in their optical properties.

SECOND ORIENTATION.

In the second possible orientation the large face is made the macropinacoid a, {100)} As the optical axial plane of variscite is parallel 

to this pinacoid, such an orientation would bring variscite into optical 

conformity with scorodite and strengite. It then becomes necessary, 

however, in order to retain the crystallographic analogy, to give to 

th<j prism m the symbol {340}. Tke dome e then becomes {102}, and 

the close angular agreement of the minerals in this position can be 

seen by the following table:

Comparison of angles (second orientation).

Angle.

b/\m=(WO) :(34.0)............

6/\e=(100) :(102)............

Variscite.

0 /

48 10 

61 17

Scorodite.

0 /

49 11 

61 02

Strengite.

0 /

49 05 

60 24

Phosphosiderite .

(1)

0 /

47 39 

60 19

(2)

0 /

49 28 

58 43

On the basis of the above angular values, the following comparison 

of the axial ratios is made:

Comparison of axial ratios (second orientation).

Mineral.

Scorodite ..................................................

Phosphosiclerite (2) ........................................

a axis.

0. 8379

.8658

.8652

.8229

.8772

c axis.

0. 9181

.9541

.9827

. 9381

1. 0660

The agreement in values is much closer than for the first orientation, 

but the prism form loses its simple indices. It must be said, however, 

that this orientation has much to commend it and may, perhaps, be 

chosen in the future as the best one for the mineral, especially when
62 MINERALOGICAL NOTES SERIES 2.

the properties of strengite and barrandite are better defined than 

they are at present. .

THIRD ORIENTATION.

A third orientation is made still possible by considering the large 

face as the basal pinacoid. Though the angular values derived from 

this orientation show a close agreement, such a habit is entirely at 

variance with all the other minerals of this group and the choice of 

orientation must be left to the first or second one.

By making the large face the basal pinacoid and taking m as {101} 

and e as {021}, the following comparison is obtained.

Comparison of angles (third orientation}.

Angle.

&Am=(001) : (101).............

W-(OOl) :(021)............

Variscite.

0 /

48 10 

61 17

Scorodite.

0 /

47 47 

62 20

Strengite.

o /

48 38 

63 02

Phosphosiderite .

(1)

0 /

48 45 

61 57

(2) 

»

0 /

50 33 

64 52

From these values the following axial ratios are obtained:

Comparison of axial ratios (third orientation).

Mineral.

Phosphosiderite (1) ......................................

Phosphosiderite (2) ........................................

a axis.

0. 8170

.8658

.8652

892Q

.8772

c axis.

0. 9126

.9541

. 9827

.9381

1. 0660

TWIN CRYSTAL.

A twin crystal was observed under the microscope among the 

crushed aggregate. The twinning plane is {102}, as the inclination 

of the twinned part of the complex to the untwinned part was measured as 31° and the angle (001): (102) is calculated as 31° 28'. Similar 

twins were noted on phosphosiderite, again showing the striking 

crystallographic closeness of variscite with phosphosiderite, and 

emphasizing the probable identity of phosphosiderite with strengite.

RELATION TO ANALOGOUS MINERALS.

The angular values for the minerals of this group are so close in 

three different directions that great care must be exercised in choosing 

the correct position. This should always be verified optically, if
CRYSTALLIZED VARISCITE FROM UTAH. 63.

possible, for on poor crystals it would be difficult to distinguish with 

certainty some of the angles. This similarity in angular values can be 

well shown by the following table:

Comparison of angles showing similarity.

Angle.

100 

010 

001 : 

010) 

001): 

100):

340)....................

110)....................

101)....................

012) ................... 021)'....................

102) ...................

9

Variscite.

0 /

' 50 03 

48 10 

50 45 

61 17 

65 28 

58 32

Scorodite.

0 /

49 11 

49 07 

47 47 

64 30 

62 20 

61 02

Strengite.

o /

49 05 

49 08 

48 38 

63 50 

63 02 

60 24

Phosphosiderite.

0 /

47 39 

50 33 

48 45 

64 52 

61 57 

60 19

o /

49 28 

48 45 

50 33 

61 57 

64 52 

58 43

It is possible that the mineral vilateite, 1 the violet crystals of Des 

Cloizeaux's hureaulite, may belong to this group. The Crystals are 

described as monoclinic, but the angular differences from orthorhombic symmetry are slight, and Lacroix states that optically the 

mineral behaves somewhat like an orthorhombic substance. The 

similarity in axial ratios to scorodite and the other minerals of the 

group can be seen in the following table. For vilateite, half the a 

axis, as given by Lacroix, has been taken.

Comparison of axial ratios.

,

Scorodite. . .................'....................

Phosphosiderite (1) ...............................

a axis.

0. 8479

.8379

.8678

.8652

.8229

c axis .

0. 8886

.9181

.9583

.9827

.9381

f

0 /

89 27

90 00

90 00

90 00

90 00

n Second orientation.

CHEMICAL COMPOSITION.

GENERAL PROPERTIES.

The mineral is infusible before the blowpipe, but, as has been stated, 

changes its color in a striking way,.the emerald green becoming a deep 

lavender and the crystals taking on a much more brilliant luster. 

Quantitative analyses show that all the water of the mineral is given 

off while the change of color is taking place, so that the lavender variscite is anhydrous. Chester 2 mentions a similar change in color for the 

variscite from Arkansas, but his investigations seem to have been generally overlooked. In describing the properties of the crystallized

1 Lacroix, A., Mingralogie de la France, vol. 4,1910, p. 477.

2 Chester, A. H., On the identity of the so-called peganite of Arkansas with the variscite of Breithaupt 

and callainite of Damour: Am- Jour. Sci., 3d ser., vol. 13,1877, p. 295,
64 MINEKALOGICAL NOTES SEEIES 2.

variscite Chester says: "The colors observed are deep emerald-green. 

* * * Before the blowpipe it becomes opaque, friable, and of a 

deep purple when hot, lighter purple when cold. In the glass tube 

yields much water and changes in color as above." The density of 

the green mineral was found to be 2.54.

The powdered mineral is insoluble in boiling hydrochloric acid, but 

readily dissolves in acids after dehydration and change in color. The 

striking color changes observed in the mineral led me to look especially for such rarer elements as had a strong chromatic effect. This 

search showed that chromium and vanadium were present in small 

amount and that a trace of iron occurred.

CHEMICAL ANALYSIS.

The results of the quantitative analysis and^the ratios deduced 

therefrom are here given:

Analysis and ratios of crystallized variscite from Lutin, Utah.

H20....................................................

P208 .. ...................................................

V2 03 . ..................................................

Cr203 - ..................................................

Fe203 - ...................................................

A12 03 ...................................................

Ni, Co, Cu ................................................

Mn, As. .................................................

Ca, Mg. .................................................

Analysis.

22.68

44.73

.32

.18

.06

32.40

I

wnnp

100. 37

Ratio.

1.260 4

.315 1

.0021

.OOll j

. 3" is'J

00

00

02

The ratios agree very well with the formula A12 03 .P2 05 .4H2 0, thus 

comparing with strengite (Fe2O3 .P2 05 .4H2O) and not with phosphosiderite (Fe203 .P205 .3iH20), even though the crystals of variscite are 

much closer in angular values to those of phosphosiderite than to those 

of strengite. 

. The results obtained as to loss of water at different temperatures are

as follows:

Loss of water on heating.

Temperature.

°C.

110 (first day). . .......................

110 (third day). ........................

140. ...................................

160....................................

Color of powdered 

sample.

.....do...... ...........

Lavender. .............

Loss of 

water.

Per cent.

5.09

9.67

12.48

19. 81

22.50

o The color here called light gray is very difficult to define. The mineral powder had lost its original 

green color but did not show any decided lavender shade. Perhaps the combination of somo lavendei 

and some green gave the resultant effect here called gray.
CRYSTALLIZED VARISCITE FROM UTAH. 65

The vanadium and chromium were determined on a 4-gram 

portion of the mineral, the method used being that described by 

Hillebrand. 1 After the chromium had been determined colorimetrically, the correction necessary to apply to the vanadium determination was found by titrating a hot sulphuric acid solution of sodium 

chromate containing the same amount of Cr203 as was present in 

the sample of variscite analyzed. Qualitative tests with ferricyanide showed that there w'as no ferrous iron in the solution of the 

mineral which had been heated to 170°. It was, therefore, possible to determine the state of oxidation of the vanadium. For this 

purpose a gram of the mineral was heated to 160°, which process 

completely dehydrated it and changed its green color to an intense 

lavender. The powdered mineral was then dissolved in sulphuric 

acid and titrated with permanganate. The amount consumed was 

equivalent to 0.45 per cent V203; or, corrected for the chromium 

present, 0.41 per .cent V2O3 . This is higher than the value obtained 

on the 4-gram sample (0.32 per cent), but the lower result is 

regarded as the more accurate. It may be here stated that a cold 

solution of bichromate in sulphuric acid will consume a small but 

appreciable amount of permanganate, which has to be determined 

and allowed for in such instances as the present one. The ferric iron 

was determined colorimetrically, using potassium sulphocyanide.

An adequate explanation of the remarkable color change and of 

the accompanying changes in physical and optical properties has not 

been found.

1 Hillebrand, W. F., The analysis of silicate and carbonate rocks: Bull. U. S. Geol. Survey No. 422,1910. 

23590° Bull. 509 12 5
HINSDALITE FROM COLORADO. 

INTRODUCTION.

In the description of the new mineral hinsdalite 1 it was stated 

that it was collected by Mr. E. S. Larsen in the summer of 1910 while 

he was engaged in the areal mapping of the geology of the San Cristobal quadrangle, Colorado. The mineral was found in considerable 

quantity at an elevation of about 9,950 feet on one of the dumps of 

the Golden Fleece mine, which is about 3 miles south of Lake City, 

Hinsdale County, Colo. The chemical analysis showed hinsdalite 

to be a hydrous sulphate and phosphate of lead- and aluminum with a 

little strontium replacing the lead. It is therefore the lead analogue 

of svanbergite, or the aluminum.analogue of corkite.

OCCURRENCE.

Mr. Larsen states that the country rock of the mineral occurrence 

belongs to the Picayune member of the Silverton volcanic series and 

consists of tuffs, lava flows, and intrusive bodies of rhyolite, latite, 

and andesite. The tunnel of the mine was not accessible, but from 

the material on the dump the new mineral appears to occur as an 

original component of a vein whose chief constituents, in the order 

of their abundance are quartz, hinsdalite, barite, pyrite, galenite, 

tetrahedrite, and rhodochrosite. The vein material contains bands 

of almost pure, coarsely granular hinsdalite, an inch or more across. 

These bands are bordered by a finely crystalline aggregate, of quartz 

and hinsdalite in which are embedded well-formed crystals, many of 

them a centimeter across, of the new mineral. Beyond the fine 

aggregate is nearly pure granular quartz or quartz and barite. The 

galenite and tetrahedrite, and to some extent the pyrite, are concentrated in the quartz-hinsdalite aggregate.

DESCRIPTION OF MINERAL.

The following description of the mineral is by Mr. Larsen: 1

The granular hinsdalite is rather coarsely crystalline and the mineral shows a strong 

tendency to develop crystal faces. Some of the larger embedded crystals are rhombohedrons resembling cubes, with a perfect cleavage (basal) truncating one corner.

i Larsen, E. S., and Schaller, W. T., Hinsdalite, a new mineral: Am. Jour. Sci., 4th ser., vol. 32,1911, p. 

251.

66 
HINSDALITE FROM COLORADO. 67

The crystal faces are always dull and rough, so that accurate measurements were 

impossible. Several crystals, however, could be measured with a contact goniometer 

and gave for the angle r/^ the values: 91.0°, 91.3°, 91.2°, 91.7°, average 91.3° or 

91° 18'. The value of the c axis computed from this average angle is 1.2677. Measurements of the angle between the cleavage and the adjacent rhombohedron varied 

from 56° to 59° with an average of 57° 18'. The calculated value for the angle c/\r 

is 55° 40'.

The faces commonly developed on the larger crystals are the unit rhombohedron 

r{ lOll} and the base c {0001}. The smaller crystals are tabular parallel to the base and 

have both the positive and negative rhombohedrons. The basal sections are hexagonal, while the prismatic sections are lath-shaped with pointed ends. The optical 

properties show, however, that the mineral is only pseudorhombohedral.

The perfect basal cleavage gives wavy and striated surfaces and the striations are in 

some cases developed in three directions, forming hexagonal markings. The hardness 

of hinsdalite is about 4.5 and the density is 3.65. The streak is colorless. The luster 

is vitreous to greasy. The crystals are nearly colorless, with a greenish cast, but much 

of the mineral is dark gray from minute inclusions.

A microscopic study of thin sections revealed the fact that the larger crystals, at least,

are strongly zoned. This zonal structure is easily seen in ordinary light or even in the 

hand specimens. Some of the zones are much more subject to alteration than others. 

Between crossed nicols the different zones show slightly different interference colors^

On account of the zonal growth it is not possible to obtain accurate and consistent 

optical data. Cleavage pieces of the mineral are not isotropic but are nearly normal 

to a positive, acute, bisectrix. The values of 2E vary from nearly 0° to 40°. Dispersion of the optic axes were not perceptible. In many cases the core of the larger 

crystals is nearly uniaxial and the most common value of 2E for the outer zones is 32°. 

The variation in the value of 2E is probably largely due to the zonal growths, though 

in some cases it is clearly due to overlapping of twin lamellae. Basal sections of some 

of the crystals are divided into six radial segments and the plane of the optic axes for 

each segment is normal to the hexagonal prism edge and to the striations.

Accurate measurements of the angle between the segments was not feasible, though 

it approximates closely to 60°. Similar optical anomalies have been described for hamlinite l and for jarosite, 2 both members of the same series of minerals to which hinsdalite belongs. 3

The indices of refraction for hinsdalite were determined by the oil-immersion 

method. The values of a and /? are nearly the same and vary from 1.66 to 1.68, with 

an average value of 1.67; the value of T varies from 1.678 to 1.700. The birefringence 

was measured by comparing the interference color of sections parallel to the plane of 

the optic axes with that of the same section of quartz. For the greater part of the 

hinsdalite crystal, the value 0.019 was obtained. Some of the narrow zones gave a 

value as low as 0.016. Therefore the indices of refraction for hinsdalite may be taken 

as: 0=1.670, r=1.671, y=1.689.

CHEMICAL COMPOSITION.

The mineral is infusible, becomes blue when heated with cobalt 

nitrate, and gives a lead reaction when fused with sodium carbonate 

on charcoal. A little water is given off when it is heated in a closed 

tube. It is practically insoluble in acids.

i Bowman,H.L., On hamlinite from the Binnenthal, Switzerland: Mineralog. Mag., vol. 14,1907, p. 389. 

* Slavik, Franz, Mineralogischo Notizen: Zeitschr. Kryst. Min., vol. 39,1904, p. 297. 

a See the following paper in this volume.
68 MINERALOGICAL NOTES SERIES 2.

After the qualitative analysis had shown what the essential components of the mineral were, a preliminary quantitative analysis was 

made, the results of which, though approximately correct, are not 

here given. With a knowledge of the composition and the experience 

gained in making the preliminary analyses, the chemical composition of hinsdalite was determined on carefully selected pure material. 

The results obtained, together with the ratios deduced therefrom, 

are shown below:

Analysis and ratios of hinsdalite.

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

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

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

Al208 .-> . --- - ---- - --

SO,.........................:........:.-...

p o

i$.Y.y.::::::::::::::::::::::::::::::::::

Per cent.

31. 75 

3.11 

Trace. 

26.47 

14.13 

14.50 

10.25

100. 21

Ratio.

0.1421 172 .030/- 17J

.260 

.177 

.102 

.570

1. 93 or 2

2. 92 or 3 

199 or 2 

1. 14 or 1 

6. 40 or 6

The ratios agree well with the formula 2Pb0.3Al2 03 .2S03 .P205 .6H2O, 

except that the P2 05 and H2O are a little high. A comparison of the 

analysis with the calculated percentages is shown below. The sample 

analyzed consists of 82.56 per cent of 2Pb0.3Al2 03 .2SO3 .P2 05 .6H2O 

and 17.44 per cent of 2SrO.3Al2 03 .2S03 .P205 .6H20 (svanbergite).

Under 1 is given, in the table below, the analysis of the Colorado 

mineral; under 2 the calculated composition of 2Pb0.3Al2 03 .2S03 .- 

P205 .6H20; under 3 the composition calculated for a mixture of 

82.56 per cent of the pure lead compound and 17.44 per cent of the 

pure strontium compound (svanbergite), and under 4, for comparison, the calculated composition of pure svanbergite.

Comparison of analysis with calculated composition.

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

SrO... .......:.........................

A1203 .................................. so23 .L. ............. --. .............

P3O5 ... ...... ...........................

H205..... .............................

1

31.75

3.11

26.47

14.13

14.50

10.25

100. 21

2

38. 37

26.36

13.77

12.21

9.29

100. 00

3

31.68

3.91

27.55

14.39

12.76

9.71

100. 00

4

22.43

33.19

17.32

15.37

11.69

100. 00

The Colorado mineral, or at least that sample of it which was 

analyzed, represents a strontium hinsdalite just as the only good 

analysis of svanbergite really represents a lead svanbergite.
HINSDALITE FROM COLORADO. 69

The water of the mineral is all water of constitution that is, it is 

driven off only at a high temperature. Practically no water was 

expelled up to 390°. The following table shows the results obtained:

Loss of water.

Temperature.

°C.

110

170

250

390

590

Total loss in

weight.

Per cent.

0.02

.02

.08

.08

9.24

The crucible was heated in an air oven up to 250°, above which 

temperature an electric furnace was used. The results show that 

the water is lost between 400° and 600°, approximately.

In its relation to other members of the group, hinsdalite is best 

considered as the lead type of svanbergite. It may just as well be 

considered an aluminous corkite, the formula for corkite l being 

2Pb0.3Fe2 03 .2S03.P205 .6H20. The systematic place of hinsdalite is 

thus well fixed. It adds another well-defined mineral to a group 

which already includes a considerable number of minerals.2 The 

relations of these minerals are shown by the following tabulation:

Svanbergite... .2SrO. 3A1203 . 2S03 . P206 . 6H20.

Hinsdalite......2PbO. 3A1203. 2S03 . P206 . 6H20.

Corkite.........2PbO. 3Fe203 . 2S03 . P205 . 6H20.

Beudantite.... .2PbO. 3Fe203. 2S03 . As205 . 6H20.

Rhomb. c=1.2063. 

Rhomb. c=i:2677. 

Rhomb. c=1.1842. 

Rhomb. c=1.1842.

1 Cf. Lacroix, A., Minfiralogie do la France, vol. 4, 1911, p. 596. 

? See following paper in this volume.
THE ALUNITE-BEUDANTITE GROUP. 

INTRODUCTION.

The analysis of the mineral hinsdalite, described in the preceding 

paper, led me to review carefully the various minerals forming the 

alunite-beudantite group. This review has brought out several 

points in regard to the relationships of some of these minerals about 

which it is very desirable to obtain more definite and accurate information. Some of the suggestions offered in this paper mus,t remain 

unsettled until such new work can be performed. Prior * has compared the various minerals belonging to this group and has clearly 

shown their similarity in composition and in crystal form. Before 

this comparison is repeated here, a short discussion of the members 

or possible members of this group will be given.

PROBABLE IDENTITY OF HAMLINITE WITH GOYAZITE.

Goyazite was described by Damour 2 in 1884 as a hydrous phosphate of alumina and lime, the rather improbable formula 3CaO.- 

5A1203 .P205 .9H20 being given for it. Hussak 3 has recently tested 

the original specimens of Damour, and has found strontium to be 

present in greater amount than lime, so that goyazite is, in reality, a 

hydrous phosphate of alumina and strontia. Hartley, in analyzing 

plumbogummite,4 has suggested that the accuracy of Damour's separation of P205 from A1203 is open to serious question because of the 

method used. If a similar inaccuracy is true for his analysis of goyazite, an interesting conclusion becomes at once evident namely that 

the mineral described and analyzed by Penfield and named by him 

hamlinite is identical with goyazite. The probable identity of goyazite and hamlinite can be best shown by a comparison of their properties.

1 Prior, G. T., Note on a connection between the molecular volume and chemical composition of some 

crystallographically similar minerals: Mineralog. Mag., vol. 13, 1903, p. 217.

2 Bull. Soc. min. franc., vol. 7, 1884, p. 204.

s Hussak, E., Uber die sogenannten "Phosphat-Favas" der diamentfuhrenden Sande Brasiliens: Min. 

pet. Mitt., vol. 25, 1906, p. 335.

4 Hartley, E. G. J., On the constitution of the natural arsenates and phosphates: Mineralog. Mag., vol. 

12,1900,^.223,225.

70
THE ALUNITE-BEUDANTITE GROUP. 71

Comparison of goyazite and hamlinit . 

Goyazlte. Hamlinlte.

Yellowish, white.-

Semitrangparent.

Uniaxial, positive.

Tetragonal or hexagonal.

Cleavage, basal.

H=5.

G=3.26.

Per cent A1203+P205 ^65.53.

Fuses with difficulty.

Colorless, yellowish.

Transparent.

Uniaxial, positive.

Hexagonal (rhombohedral).

Cleavage, basal.

H=4.5.

0=3.228, 3.159-3.283.

Per cent A1203+P205=62.87.

Fuses about 4.

The hamlinite from Maine contains a little barium and fluorine, but 

their amount, in comparison to that of strontium and water (hydroxyl) , respectively, is small. Moreover, the absence of barium and 

fluorine in goyazite has not been established.

UTAHITE AND RELATED MINERALS.

On the basis of our present knowledge, utahite, cyprusitfe, raimondite, pastreite, carphosiderite, and apatelite form a group of minerals 

which are very closely related. They are all hydrous sulphates of 

ferric iron with very similar quantitative composition, and all occur 

in hexagonal or rhombohedral scales. The only one of these minerals 

which has been found in measurable crystals is utahite, for which two 

values for the c axis have been given, namely, 1.1389 and 1.0576. If 

it is considered that the material analyzed was many times of doubtful purity and that perhaps the analytical methods used were not 

always of the best, the differences in their analytical figures become of 

minor importance, and it seems almost justifiable to regard them all 

as identical. They may be placed chemically in three divisions, 

according to their formulas, as follows :

I. Utahite. ........... .3Fe203 .3S03 .6H20.

f Carphosiderite. .... .3Fe203 .4S03 .10H20.

11 ' I Apatelite. ......:.. .3(Fe,Al)203 .3S03 .9H20.

[Raimondite.... . .... .2Fe203 .3S03 .7H20.

III. j Pastreite..... . ...... .2Fe203 .3S03 .7H20.

[Cyprusite .......... .4(Fe,Al)203 .5S03 .7H20.

These different formulas are all very closely related and when it is 

considered that, so far as the published descriptions go, the crystalline form of all these minerals is the same, it seems reasonable to regard 

them as identical. The above formulas are all close to

3Fe203 .4S03 .7H20,

though to none of the minerals has this formula been ascribed. This 

formula corresponds to that of a j arosite in which the K2O is replaced 

by H20, as will be evident from the following comparison:

.Jarosite. ....... .K2Q3Fe2

New formula. . . .H20.3Fe203 .4S03 .6H20.
72 MINERALOGICAL NOTES SEEIES 2.

The formulas of carphosiderite and apatelite l may be expressed in 

similar form, for these minerals differ from the type only in containing a slightly greater amount of water:

Carphosiderite=H20.3Fe203 .4S03 .6H2O + 3H20.

I would therefore propose that, unless careful work proves to the 

contrary, carphosiderite, apatelite, raimondite, pastreite, cyprusite, 

and utahite be regarded as the same mineral with the formula 

H20.3Fe203 .4S03 .6H20, and that to this mineral the name carphosiderite be applied by right of priority.

The compilation of analyses of these minerals, given in the accompanying table, shows their close chemical relationship and their general agreement with the formula H20.3Fe203.4S03 .6H20.

1 Apatelite is only an aluminous carphosiderite.
Analyses of carphosiderite.

H20......... .............................

S08 .......................................

Fe203 ....................................

AL,03 . ...................................

X."............ ...........................

Calculated.

13.5 

34.7 

51.8

100.0

Utahite.

1

9.35

28.45 

58.82

&3.19

99.81

2o

[12.41] 

26.83 

58.51

c2.19

100. 00

Cyprusite.

11.06 

35.34 

49.68 

3.89

99. 97 

1.7-1.8!

Past

1

16.04 

30.47 

46.50

d 6. 40

99.41

o Arzrani and Thaddeefl, Zeitschr. Kryst. Min., vol. 31, p. 244. 

6 As2O5 . 

c insoluble.

<J SiO2, 2.40; As2

e As2O5, 2.05;' (A

/ PjOs.
74 MINEKALOGICAL NOTES SERIES 2. 

MISCELLANEOUS NOTES.

Though the members of^, the group are uniaxial rhombohedral, yet 

optical anomalies indicating biaxiality have been noted for a sulphate (jarosite), a phosphate (hamlinite), and a compound sulphatephosphate (hinsdalite). Jarosite has been described as showing 

optical anomaly by Slavik/ who found that jarosite from Schlaggenwald showed, in basal section, a division into six parts, each part 

Toeing biaxial, the trace of the axial plane normal to the prism edge. 

The negative, biaxial interference figure varied in siz6 in different 

crystals, up to 32°. Some basal plates were pleochroic and decidedly 

doubly refracting.

Hamlinite 2 from Switzerland, at first thought to be a new species 

and called bowmanite, 3 shows optical anomalies. The larger crystals show a division into six sections, each showing a positive, biaxial 

figure, 2E varying from 0° to 50°. Hinsdalite likewise shows a 

pseudohexagonal character,4 the crystals being built up of six sectors, 

each normal to an acute bisectrix, 2E varying from 0° to 40°. These 

optical anomalies are very suggestive of dimorphism in the series.

The isomorphous relation of sulphate and phosphate is still further confirmed by the presence of 2.72 per cent P205 in an analysis 

of carphosiderite from France and also by the presence of nearly 1 

per cent P2 05 in a sample of alunite from Utah, tested by the writer.

The formulas of beudantite and corkite have been taken as suggested by Lacroix 5 ; the arsenate has been called beudantite and 

the phosphate corkite. The composition of miriquidite, munkforssite, and munkrudite are too little known to include them definitely in this group, although their qualitative composition suggests 

that they belong to it.

Pharmacosiderite has been shown 6 to contain considerable potash, and Hartley's formula, 2FeAs04 .Fe[0(HK)]3.5H2O, can be 

written in such a form as to show its analogy to hamlinite, as 

2(H,K) 20.3Fe2 03 .2As205 .7H20 + 4H20, in which formula the 4H2O does 

not really belong to the mineral. Though pharmacosiderite is considered isometric, the form is very similar to the rhombohedral crystals 

of this group, and it would be highly desirable to test the mineral 

optically to see if it could be referred, to a uniaxial mineral, as it 

commonly shows weak double refraction.

The composition of plumbogummite still needs careful study, for 

it is entirely possible that more than one species is included under

1 Slavik, Franz, Mineralogische Notizen: Zeitschr. Kryst. Min., vol. 39,1904, p. 297.

3 The name hamlinite is retained until its identity with or distinction from goyazite is definitely 

determined. *"'

3 Bowman, H. L., On hamlinite from Binnenthal, Switzerland: Mineralog. Mag., vol. 14,1907, p. 389.

< See the preceding paper in this volume.

6 Lacroix, A., Mine'ralogio de la France, vol. 4,1910, p. 592.

»Hartley, E. G. J., On the constitution of the natural arsenates and phosphates: Mineralog. Mag., vol. 

12,1899, p. 152.
THE ALUNITE-BEUDANTITE GROUP. 75

that name. The analyses of Hartley have established the presence 

in quantity of C02 in some varieties, while the analyses of Brazilian 

plumbogummite, given by Hussak, are free from any C02 , although 

these latter contain more water than is usual. Perhaps the fine 

grinding of the samples has a very marked effect on the water content of these minerals, as Hartley has suggested for pharmacosiderite. 

The mineral caUed harttite is an isomorphous mixture of about 

two parts of hamlinite and one part of a strontium alunite. More 

accurately the ratio is 1.97 parts to 1 instead of exactly 2 to 1. 

Its formula may therefore be written 2[2Sr0.3Al203 .2P2 05 .7H2 0] + 

l[Sr0.3Al203 .4S03 .6H20], which can be simplified to 5Sr0.9Al203 . 

4P2O5 .4S03 .20H20. This is very close to the formula deduced by Hussak, which when quadrupled becomes 4SrO.8Al2 03 .4P2 05 .4S03 .20H2 0. 

In fact, the ratios deduced by Hussak from the analysis of harttite 

are in better agreement with the formula here proposed than with 

his own.

Ratios of harttite.

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

A] 2 03 .. ...........................

PO

so3 ... ............................

H20..............................

Ratio of analysis.

1664 

3355 

1528 

1475 

1733

4.57 

9.22 

4.20 

4.05 

19.60

Required 

by Hussak' s formula.

4.00 

8.00 

4.00 

4.00 

20.00

Required 

by Schaller's formula (approximately).

5.00 

9.00 

4.00 

4.00 

20.00

CLASSIFICATION OF MINERALS OF THE GROUP.

The minerals forming the alunite-beudantite group may be divided 

into three smaller groups, the sulphates, the phosphates, and the 

sulphate-phosphates.. Taking alunite as the type of the sulphates, 

hamlinite of the phosphates, and corkite as that of the sulphatephosphates, we have:

Alunite. ..... K20. 3A1203 .4S03 .6H20.

Hamlinite.... 2SrO. 3A120.2P205 .7H20.

Corkite..... .2Pb0.3Fe203 .2S03 .P205 -6H20.

The analogous composition is not clearly seen in the three formulas 

just given, but it is possible, by rewriting them in a slightly different 

foim, to show very clearly the analogy between them:

Alunite.......K20.3A1203 .6H20.2S03 .2S03 .

Hamlinite.... Sr0.3Al203 .6H20.2HP03 .Sr(P03 )2 .

Corkite..... Pb0.3Fe203 .6H2O.2S03 .Pb(P03)2 .
76 MINEEALOGICAL NOTES SERIES 2.

By assuming the isomorphous replacement of S03 by HP03 , the 

relationships become very clear. The formula can be, however, 

better written by regarding = [S04] and = [HPOJ as the isomorphous 

groups which are replaceable. The formulas for these minerals then 

become:

Alunite...... .[A1(OH)2]6.K2 .[S04]2 . [S04]2 .

Hamlinite ...[Al(OH)2]6.Sr. [HP04]2 .[Sr(P04)2]. 

Corkite......[Fe(OH)2 ]6.Pb.[S04]2 . [Pb(P04 )2].

The general formula is written

[R'''(OH) 2]6 .R''.[M]2 .[M]2, 

in which

R"'=A1, Fe'".

R" =K2 , Na2 , H2 , Pb, Sr, Ba.

M = S04 , HP04 , HAs04 , PbjP04 , SrjP04 .

The entire group then consists of the following minerals:

Sulphates. Type formula [R'"(OH)2]5 .R'2 or £".[.S04]2 .[S04]2 .

Alunite............[A1(OH)2] 6 .K2 .[S04]2 .[S04 ]2 .

Natroalunite. .....[Al(OH)2]6 .Na2 .[S04]2 .[S04 ]2 .

Jarosite.......... .[Fe(OH)2] 6 .K2 .[S04]2 .[S04]2 .

Natrojarosite..... .[Fe(OH) 2]6 .Na2 .[S04]2 .[S04 ]2 .

Plumbojarosite... .[Fe(OH)2] 6 .Pb.[S04]2 .[S04 f2 .

Carphosiderite.... .[Fe(OH)2] 6 .H2 .[S04]2 .[SOJ2 .

Phosphates. Type formula [R^^OH^.R^.[R'PO^

Hamlinite....... .[A1(OH)2 ] 6 .Sr.[ HP04 ]2 .[ Sr(P04 ) 2 ].

Plumbogummite ..[Al(OH)2]6 .Pb.[ HP04]2 .[Pb(P04)2]. 

Gorceixite........[Al(OH)2]6 .Ba.[ HP04]2 .[Ba(P04 )2].

Florencite....... .[Al(OH) 2]6 .Ce§.[CejP04]2 .[Cei(P04 ) 2 ].

Sulphate-phosphates. Type formula [R'"(OH)2}6 .R" .[SO 4

Beudantite.....?.. [ Fe(OH)2]6 .Pb.[S04]2 .[Pb(As04 ) 2].

Corkite...........[ Fe(OH)2]6 .Pb.[S04]2 .[Pb(P04 )2j.

Svanbergite....... [ Al(OH)2 ] 6 .Sr.[S04]2 .[Sr(P04 ) 2].

Hinsdalite. .......[ Al(OH)2]6 .Pb.[S04]2 .[Pb(P04 )2j.

Harttite jt Al(OH) 2] 6 .Sr.[S04]2 .[S04 ]2 .

 - l2([Al(OH)2] 6 .Sr.[HP04 ]2 .[Sr(P04 )2]).
SOME MINERALS FROM BEAVER COUNTY, UTAH. 

INTRODUCTION.

While making an examination of some of the mines in Beaver 

County, Utah, in the summers of 1909 and 1910, Mr. B. S. Butler, of 

the United States Geological Survey, collected several minerals that on 

examination proved to be of unusual interest. One of these is a 

species not hitherto known, a second has never before been reported 

from this continent, and a third, although previously reported from 

but two localities, was found to be relatively abundant in this

district.

BEAVERITE.

From the Horn Silver mine, near the town of Frisco, a mineral was 

obtained that proved on examination in the laboratories of the United 

States Geological Survey to be a new species. For this mineral, 

which is a hydrous sulphate of copper, lead, and ferric iron, the name 

beaverite was proposed,1 after the name of the county from which it 

was first described.

OCCURRENCE AND ASSOCIATION.

As described by Butler, the mineralization in the Horn Silver mine 

occurs along a fault plane that has thrown Tertiary lavas down against 

Cambro-Ordovician limestone, the ore deposits being mainly a 

replacement of the volcanic rocks. The principal primary minerals 

of the deposit are galena, sphalerite, wurtzite, pyrite, chalcopyrite, a 

sulphantimonite of lead possibly jamesonite, pyrargyrite, argentite, 

quartz, barite, and sericite. The mine has been developed to a depth 

of 1,600 feet. For about 600 feet the primary minerals have been 

almost entirely altered by descending solutions, and this alteration 

has taken place in lesser degree to a much greater depth. The 

characteristic alteration in the deposit is to sulphates, with some 

secondary carbonates, chlorides, and sulphides. The following secondary minerals have been recognized: Anglesite, cerussite, plumbojarosite, jarosite, beaverite, linarite, bindheimite?, smithsonite, calamine, goslarite, covellite, chalcocite, brochantite, malachite, azurite, 

chyrsocolla, chalcanthite, cerargyrite, sulphur, chalcedony, kaolinite, 

gypsum, alunite, and hydrous oxides of iron and manganese. The 

beaverite occurs with other secondary minerals in the upper part of

1 Butler, B. S., and Schaller, W. T., Some minerals from Beaver County, Utah: Am. Jour. Scl., 4th 

ser.,vol. 32, 1911, p. 418.

77
78 MINERALOGICAL NOTES SERIES 2.

the deposit. Only a small portion of the upper levels was accessible 

at the time of visit and the mineral was not seen in place, but the 

frequency with which it was met in the old dumps leads to the belief 

that it must have been rather common in some parts of the deposit.

PHYSICAL PROPERTIES.

The mineral is a canary-yellow material of earthy appearance, 

commonly mixed with other secondary lead and copper minerals, 

but of less common occurrence in small masses that appear to be 

composed of a single mineral. Such masses are easily crushed in the 

fingers. Under the high power of the microscope the material is 

seen to be crystallized in distinct hexagonal plates, too small for 

accurate measurement of the crystal angles or for determination of 

the optical character. The refractive index of the light ray vibrating 

perpendicular to the plates is higher than 1.74.

Almost every crystal contains a minute inclusion whose character 

has not been determined. The material analyzed appeared under 

the microscope to be very pure except for these inclusions, and it is 

possible that the silica that appears in the analyses is due to them.

CHEMICAL COMPOSITION.

The mineral is soluble in boiling hydrochloric acid, leaving the. 

insoluble matter, chiefly silica, behind. On cooling, lead chloride 

separates out in considerable amounts. The lead reaction can also 

be readily obtained with sodium carbonate on charcoal. On adding 

ammonia in excess to the hydrochloric acid solution, the ferric iron 

is thrown down as a voluminous brown precipitate and the solution 

takes the deep blue color indicative of copper. By quantitative 

determination the presence of a small amount of alumina was established. The insoluble matter consists mostly of silica, only a slight 

residue remaining after treatment with hydrofluoric acid.

The average of the results of the chemical analyses is shown in the 

table below. The ratios obtained therefrom are also given.

Analysis and ratios of beaverite.

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

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

Fe203 . ....................................

A1203 - ------------------------------------

en^v.:.-.::::::::::::::::::::::::::::::::::

Per cent.

10. 05 

9.70 

29.44 

17.28 

3. 64 

21.32 

9.02

100. 45

Ratio.

0.121 

.132 :S}-i«

.266 

.501

0. 92 or 1 

1. 00 or 1

1. 07 or 1

2. 01 or 2 

3. 80 or 4
SOME MINERALS FROM BEAVER COUNTY, UTAH. 79

The ratios agree well with the formula CuO.PbO.Fe2 03 .2S03 .4H20, 

in which the copper and lead are assumed to be present in equal 

molecular amounts and in which a little ferric iron is replaced by 

alumina. As the ratio of Fe2 03 to A12 03 is as 3 : 1, the formula can 

be written more exactly as 4Cu0.4Pb0.3Fe2 03 .Al2 03 .8S03 .16H2 0. A 

comparison of the analysis reduced to 100 per cent after deducting 

the insoluble matter, with the values calculated for the formula last 

given, is shown below.

Comparison of analysis with calculated values.

CuO. ...................................................... Pbo............................................. .........

FeA.. .....'...............................................

A1203 ------------------------------------------------------

SOV .. ; ................................................... ^.. ................... ...................................

Analysis.

10. 74

32.50

19.13

4.03

23.60

10.00

100. 00

Calculated.

11. 70

32.80

17.61

3.75

23.54

10.60

100. 00

The water is all constitutional, as none was driven off below 250°. 

The actual results obtained are as follows:

Loss of weight of beaverite on heating.

Temperature.

°C.

110

170

250

390o

590o

Total loss.

Per cent.

0.04

.10

.14

3.72

10.45

« Heated in an electric furnace.

The loss at 590°, as given, is higher than the true value, as a little 

of the material was lost by adhering to the thermal couple, which 

accidentally dropped into the crucible.

No known mineral could be found with which beaverite seems to be 

related, so that for the present, at least, it must stand as an isolated 

member of the sulphate group.

WURTZITE.

OCCURRENCE.

The hexagonal zinc sulphide, wurtzite, is, according to Butler, 

present in considerable abundance in the primary ores of the Horn 

Silver mine. The principal primary minerals of this deposit have
80 MINERALOGICAL NOTES SERIES 2.

been noted above. The richer zinc ore, in the hand specimen, has 

the general appearance of light honey-yellow sphalerite, but under 

the microscope a portion is seen to be rather strongly birefringent, 

and some of this birefringent material has the outline of pyramidal 

crystals. Close examination of the mineral 

revealed pyramidal crystals that could be 

separated from the surrounding material.

CRYSTALLOGRAPHY.

Several of these crystals were removed from 

the matrix and measured. They showed a steep 

hexagonal pyramid which was strongly striated 

horizontally. Accurate measurements were not 

possible, as the striations caused the crystals to 

become rounded with consequent absence of 

plane faces. The crystals were measured on 

the two-circle goniometer and the p angle determined for the pyramid faces. This angle corresponds to that between the basal plane (absent 

on these crystals) and the pyramidal faces. The values obtained are 

shown below, the pyramid being the form o {2021}:

Measurements of o{2021} wurtzite.

FIGURE 5. Wurtzite, o {2021}.

Crystal No. ...................................

Average measurement .........................

1

61°

2

62°

3

60°

4

61°

Calculated value, 62° 06'.

The general habit of these crystals is shown in figure 5, in which 

the marked horizontal striae are also shown.

The crystals of wurtzite dissolve readily in hydrochloric acid, 

giving off hydrogen sulphide. The solution contained abundant 

zinc, and no other metal was present in appreciable quantity.

Butler noted that the zinc sulphides in this mine have the property 

of tribe-luminescence, or of giving out light when scratched. This 

property is so marked that sulphides of zinc can be readily detected 

in the mine by drawing the point of the pick or mine candlestick 

across the ore. If zinc sulphides are present the point of the metal is 

followed by a line of sparks.
SOME MINERALS FROM BEAVER COUNTY, UTAH. 81

PLUMB O J ARO SITE.

OCCURRENCE AND PHYSICAL PROPERTIES.

Plumbojarosite has previously been described from two localities, 

first from Cooks Peak, N. Mex.,1 and second from American Fork, 

Utah.2

Mr. Butler found this rare mineral in no less than six mines and 

prospects in Beaver County (the Horn Silver, Hub, Moscow, Red 

Warrior, and Harrington-Hickory mines, and an unnamed prospect 

pit), and in some places a considerable quantity could be picked from 

the ore bins and dumps. It was reported that several tons of the 

mineral had been thrown on the dump of one mine and later, when 

found to contain metal values, had been shipped to the smelter.

The following description of its occurrence and physical properties 

is by Butler:

The mineral is secondary, resulting from the alteration of ore composed mainly of 

sulphides of iron, lead, copper, and zinc. The secondary minerals for the most part 

are the oxides, sulphates, carbonates, and silicates of these metals, and with these are 

plumbojarosite, frequently jarosite, and other minerals in varying amounts. It is of 

interest to note that from the Horn Silver mine three members of the jarosite group 

were determined, namely, jarosite, plumbojarosite, and alunite.

As seen in the hand specimen, the material is dark brown in color and distinctly 

micaceous in appearance, with a silky luster. Where the crystals are very fine the 

micaceous character is less pronounced, and the mineral, if not examined with some 

care, might be mistaken for limonite or some iron-stained material. Although the 

mineral is frequently in rather large pieces as it comes from the mine, it is readily 

crushed in the fingers and has an oily look and feel, similar to fine graphite. Under 

the microscope the crystals are seen to be thin hexagonal plates of a light goldenyellow color. The crystals vary greatly in size but rarely exceed 0.25 mm. in width. 

Measurement of the crystals has not been made, but they are undoubtedly hexagonal, 

and,- so far as their properties have been determined, they correspond to the material 

examined by Wright from the American Fork locality. The crystals are uniaxial, 

optically negative with strong birefringence. It may be noted that the jarosite 

from the same mines is so similar to the plumbojarosite in physical properties that a 

distinction can be made only by chemical tests. .

CHEMICAL COMPOSITION.

The analysis of the plumbojarosite is shown in the table below, 

where, for comparison, are also given the two analyses, by Hillebrand, of the mineral from New Mexico and American Fork, Utah. 

The values calculated from the formula Pb0.3Fe2 03 .4S03 .6H20 are 

also given in the last column for comparison.

i Hillebrand, W. F., and Penfield, S. L., Am. Jour. Sci., 4th ser., vol. 14,1902, p. 213. 

* Hillebrand, W. F., and Wright, F. E., Am. Jour. Sci., 4th ser., vol. 30,1910, p. 191.

23590° Bull. 509 12 6
82 MINERALOGICAL NOTES SERIES 2. 

Analyses of plumbojarosite.

Fe203 ....... ................ ...........

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

K20..................................

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

SO....................................

H20..................................

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

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

ZnO... ................................

Beaver 

County, 

Utah.

42.11

18.32

1 13

) ,13

27.59

9.16

2.64

.30

100. 25 

3.60

Cook's 

Peak, 

N. Hex.

42.37

19.84

f .17

1 21

27.06

9.56

.27

.05

.51

100. 15 

3.665

American 

Fork, 

Utah.

42.87

18.46

.15

.52

27.67

10.14

.10

.06

.40

100. 37

Calculated.

42.38

19.74

28.33

9.55

100. 00

The three analyses agree closely with each other and with the 

calculated values.

CORKITE.

OCCURRENCE AND PHYSICAL PROPERTIES.

Mr. Butler states that 

A light yellowish-green mineral that has the properties of corkite, a hydrous phosphate and sulphate of lead and iron, was collected from the Harrington-Hickory and 

the Wild Bull mines. So far as is known, these are the only localities on this continent from which the mineral has been reported.

In both of the mines mentioned the original ores were a replacement of limestone 

near the intrusive rock, and considerable quantities of apatite and contact silicates 

were formed with the metallic sulphides, mainly pyrite, galena, sphalerite, and 

chalcopyrite. The corkite is a secondary mineral resulting from the alteration of 

these ores, the phosphate doubtless being derived from the apatite and the metallic 

content from the sulphides.

In physical properties the mineral corresponds with that previously described. 

In the hand specimen it is a light-green, earthy-looking material, which when crushed 

in the fingers has a gritty feel like fine sand. Under the microscope it is seen to be 

well crystallized, the larger crystals being 0.15 millimeter in diameter. The crystals 

are golden yellow and have the general appearance of being a combination of the 

cube and octohedron. They are rather strongly birefringent, however, and are probably hexagonal rhombohedral. The index of refraction is higher than 1.74.

CHEMICAL COMPOSITION.

Corkite is readily soluble in boiling hydrochloric acid, from which 

solution lead chloride separates out in quantity on cooling. The 

solution contains, besides lead, abundant ferric iron and the sulphate 

and phosphate radicles. Qualitative tests failed to show the presence 

of any arsenic, and only a mere trace of copper is present. Heated 

in a closed tube, the mineral darkens and gives off water.
FERRITUNGSTITE FROM WASHINGTON.

A sample of tungstic ocher was collected by Mr. Howland Bancroft, 

of the United States Geological Survey, from the Germania tungsten 

mine of the Deer Trail mining district, in the northeastern part of 

the State of Washington. Mr. Frank L. Hess, also of the Survey, 

suggested that the tungstic ocher might prove of sufficient interest 

to warrant careful study. On microscopic examination, the earthylooking ocher was found to be well crystallized and pure, and chemical 

tests showed that the ocher was a hydrous ferric tungstate, entirely 

different from ordinary tungstic ocher, or tungstite, which, as Walker 1 

showed, has the formula W03 .H20. For the privilege of describing 

this interesting new mineral I am deeply indebted to the two gentlemen above named.

Examination under the microscope shows that ferritungstite 

crystallizes in hexagonal plates, evenly developed but very minute. 

Those lying flat on the base are isotropic under crossed nicols but 

are too small to exhibit any interference figures. Such crystals as 

are partially tilted show decided double refraction on their edge. 

A small quantity of gangue, mostly quartz, is mixed with the mineral, 

but limonite stains are almost absent, though here and there traces 

can be seen. Probably less than one per cent of limonite is present 

in the purest ocher, such as was analyzed.

Ferritungstite results from the oxidation of wolframite and is 

associated with that mineral in massive quartz. The cleavage, hardness, and density of ferritungstite could not be determined. Its 

color is pale yellow to brownish yellow when pure. It gives off 

water in a closed tube and is decomposed by acids, yellow oxide of 

tungsten separating out.

Only a few tenths of a gram of pure material was available for 

analysis. Two samples were taken at different times from the same 

specimen. Qualitative tests showed the absence of Mo03 , S03 , 

P205 , and, in general, of substances other than those given in the 

analyses. The analyses of the two samples are given below.

' Am. Jour. Sci., 4th ser.,' vol. 25,1908, p. 305.

83
84 MINEKALOtHCAL NOTES SERIES 2. 

Analyses of ferritungstite.

W03 ......................................................

Fe£>3 .. .......................... ........................

H20 .....................................................

1

37.1

26.6

18.6

14.7

97.0

2

35.8

97 ^

20.9

[16. 0]

100.0

a HjO determined by loss on ignition.

The ratios deduced from these analyses are shown in the following 

table:

Ratios of analyses of ferritungstite.

W03 .. ............................................

Fe203 -------- ....................................

H20..............................................

1 .

0. 16 or 0. 94

. 17 or 1. 00

1. 03 or 6. 06

2

0. 15 or 0. 88

. 17 or 1. 00

1. 16 or 6. 82

These ratios are close enough to 1:1:6 to show that the formula for 

ferritungstite is Fe203 .W03 .6H2O. Below are shown the two analyses with the insoluble matter deducted and recalculated to 100 per 

cent, compared with the theoretical values calculated from the formula Fe203 .W03 .6H20.

Comparison of analyses with calculated composition.

W03 .. .........................................

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

H20.. .........................................

Analysis 

1.

45.1

32.3

22.6

100.0

Analysis 

2.

42.6

32.5

24.9

100.0

Calculated.

46.4

32.0

21.6

100.0

The mineral is different from any yet described, and the new name 

proposed, ferritungstite, shows its chemical relation to ordinary 

tungstic ocher or tungstite.
NOTES ON MINERALS FROM GABBRO OF WAIMEA 

CANYON, HAWAII.

INTRODUCTION.

The following brief crystallographic descriptions are based on 

material furnished by Dr. Whitman Cross of the United States Geographical Survey, to whom I am indebted for his kind permission to 

publish these results. The crystals were found projecting into the 

cavities of a coarse gabbro (Dr. Cross's No. 15K) bowlder in the 

stream bed about one-fourth mile up the east branch of Waimea 

Canyon, which enters the main canyon about 5 miles above the 

mouth.

APATITE.

Apatite is present in long slender needles, colorless and transparent except where covered with an opaque grayish coating. The 

crystals, when terminated, show as prominent forms only m{10TO} 

and x{10Tl}. The six faces of the unit pyramid are usually triangular m shape and not all of uniform size. Besides the two dominant forms, m and x, there were noted five other forms, all very poorly 

developed. The prism a{1120} is present as a long line face, and 

very minute striae, corresponding to faces of 7&{2130} and £{4150}, 

were also noted. The base c{0001} and the pyramid y{2021} 

were measured, the faces representing these forms being very minute 

short line faces. All the faces except some of those of m and x gave 

very poor and indistinct reflections.

The following measurements are the averages of the obtained values, 

on which the identification of the forms are based. The angles for the 

calculated values are taken from Goldschmidt's Winkeltabellen.

Measured and calculated angles of apatite.

Letter.

m. ......

h.......

k.......

x.......

y.......

Form.

1010 

1120 

2130 

4150 

0001 ion

2021

Measured.

<!>

0 /

0 00 

30 04 

18 13 

11 38

0 00 

0 00

P

0 /

90 00 

90 00 

90 00 

90 00 

1 00 

40 00 

60 00

Calculated.

<£

0 /

0 00 

30 ' 00 

19 06 

10 53

0 00 

0 00

P

0 /

90 00 

90 00 - 

90 00 

90 00 

0 00 

40 16 

59 27

85
86 MINERALOGICAL NOTES SERIES 2.

ORTHOCLASE.

A single square prism of orthoclase was suitable for measurement. 

Both ends were broken off, so that the only forms identified are 

c{001}, &{010}, and n{021}. The measurements are as follows: 

CA& = 89°50'-90° 17' (90° 00 ' calculated); I A n=45° 08' (45° 03' 

calculated).

TITANIFEROTJS AUGITE.

The crystals of augite are small, being about 3 millimeters high 

(c axis), 2£ millimeters wide.(& axis),'and slightly less than 1 millimeter thick (a axis). They are black and shining, but on the broken 

surface show the peculiar violet tinge possessed by titanium-rich 

augites.

Two crystals were found that could be measured. They both have 

the same habit, being stout tabular parallel to the orthopinacoid. 

The crystals are terminated by two large faces of the negative unit 

pyramid {Til}.

The prism zone is fairly rich in faces, there being measured 11 faces 

belonging to six forms on the first crystal and 14 faces of five forms on 

the second crystal. Two of the prisms are new for augite.

The forms observed on these two crystals are as follows, the new 

forms being starred^ a{100}, 6{010}, m{110}, J{150},- *#{230}, 

*T{530}, (/{210}, s{Tll}. The following table gives a comparison 

of the angles measured and calculated. 1

Measured and calculated angles of augite.

Letter.

&.......

J.......

e ......

r. .......

g.. .....

Symbol.

100 

010 

110 

150 

230 

530 

210 

111

Measured.

*

0 /

90 00 

0 02 

43 37 

11 12 

32 09 

58 09 

63 05 

25 34

P

0 /

90 00 

90 00 

90 00 

90 00 

90 00 

90 00 

90 00 

33 36

Calculated.

</>

0 '

90 00 

0 00 

43 33 

10 46 

32 22 

57 45 

 62 15 

25 07

P

0 /

90 00 

90 00 

90 00 

90 00 

90 00 

90 00 

90 00 

33 04

Following is given a brief description of the different forms, 

arranged, in the order of their size.

The orthopinacoid, a{100}, is by far the largest form on these 

crystals, and thereby determines then: habit. The faces are striated 

vertically, though the reflections obtained were fairly good.

i For the calculated angles the constants a : ft : c= 1.0934 :: 0.5894, 0=74° 09', are taken. These values, 

from Goldschmidt's Winkeltabellea, are almost identical with the values given for pyroxene in Dana's System of Minearalogy, 6th edition, 1892, p. 352.
MINERALS FROM WAIMEA CANYON, HAWAII. 87

All four faces of the negative pyramid s {Til} are strongly 

etched, only incomplete narrow rims of the bright shining face being 

left, but these gave fairly good reflections. This pyramid is the only 

terminal face that could be found on either crystal.

The unit prism m is generally smaller than the pyramid 5, though 

one face of m was nearly as large. The true value of the prism angle 

is probably a few minutes larger than the average value here given 

(43° 37'), as out of 10 measurements six lie between 43°. 39' and 

43° 43', but two low values slightly lower the general average.

The clmopinacoid, &{010}, is present as small faces, smaller than 

those of a{100}, m{110}, or s{Tll}, but generally larger than any of 

the other faces.

All the remaining forms are present as line faces in the prism zone. 

Of the known forms J{150} was noted but once as a small broad 

lino face. Three faces of #{210} were measured on the second 

crystal, the faces being exceedingly fine striae and the reflections very 

poor. In one no reflection could be seen. The three measured values 

are: 62° 00', 63° 56', 63° 19'; calculated, 62° 15'.

The new forms are two in number and are briefly described below:

*<9{230}. Only one face of this form, a line face, was observed 

on the first crystal. It lay between a and m and was the only face in 

this quarter of the prism zone besides ami). The reflection was 

faint but distinct. Two measurements of it gave the values 32° 05' 

32° 13'. The calculated value is 32° 22 '.

*r{530}. One face of T was noted on each crystal. The faces were 

all line faces and gave poor reflections, though the one from the first 

crystal (57° 47') was very distinct and the difference between the 

measured and calculated angles is very slight. The measurements 

were 57° 47' and 58° 30'; the average is 58° 09', and the calculated 

value 57° 45'. A third face gave a measured angle of 59° 13', and 

may possibly belong to this form.

Reflections were also measured from several other faces which 

agreed approximately for {320} and {520}, but they were too poor 

to warrant any further characterization.

The combination a{100}, m{llQ}, Z>{010}, and 8(111}, with a 

tabular habit due to the predominance of a{100} seems to be 

characteristic of these brownish-violet titanium-rich basaltic augites.
CUPRODESCLOIZITE FROM CALIFORNIA.

Some samples of reported vanadium ore, sent to the United States 

Geological Survey by Messrs. A. L. Lombard and J. F. Main, of the 

Dirigo Mining & Milling Co., of Los Angeles, Cal., proved to be coated 

with a deposit of cuprodescloizite. The associated lead minerals are 

cerusite and vanadinite, and from these the cuprodescloizite seems 

to be derived. The locality is given as Camp Signal, in San Bernardino County, Cal.

A qualitative chemical test showed the presence in quantity of 

lead, copper, zinc, and vanadium, and of a little water. A direct 

quantitative determination of the vanadium gave 21 per cent V205 .

The material, when examined under the microscope, was seen to be 

well crystallized in minute plates. Some of these were square or 

oblong; others were irregularly shaped. The rectangular plates 

gave parallel extinction, with the axial plane parallel to one of the 

sides, and with a very large axial angle. The plates are colorless or 

pale yellow. The thicker pieces are very slightly pleochroic in 

shades of yellow. The double refraction was not very high. A few 

tabular pieces showed an acute termination, the sides of which were 

inclined 52° to the trace of the axial plane. The sections, tabular 

parallel to a{100}, showed c{001}, u{Qll}, both large, and &{010} 

small.

These various data are all in harmony with the properties of 

descloizite and cuprodescloizite, to which the mineral is therefore 

referred.
MINERALOGY OF THE FRENCH PHOSPHORITES. 

INTRODUCTION.

In two recent publications, 1 Lacroix has described the mineralogy 

of the phosphorites of France and its colonies. These descriptions 

present so clearly the mineralogical composition of the phosphorites, 

that I thought it would be of interest to students of the American, 

phosphate deposits to present briefly the results reached by Lacroix.. 

The data here given are, therefore, a free translation and compilation, 

of his papers.

TYPES OF PHOSPHORITES.

The French phosphorites are of three types 

(1) Holocrystalline, fibrous; (2) amorphous (isotropic), homogeneous; (3) mixture 

of the amorphous and holocrystalline.

(1) The holocrystalline, fibrous type is composed of either dahllite 

or francolite. Dahllite is a hydrous carbonate and phosphate of 

lime, free from fluorine, and was first found in Norway, its occurrence there being described by Brogger and Backstrom 2 in 1888.. 

Tschirwinsky's podolite, described 3 as a new mineral in 1907, is. 

probably identical with dahllite. 4 Francolite was described in 1850' 

from Tavistock, Devonshire, England,5 but has hitherto been considered a variety of apatite. Staffelite 8 is considered by Lacroix: 

as identical with francolite, but the name is kept for the fibrous, 

variety of francolite. Damour's hydroapati^e 7 also is francoline.. 

Francolite is similar to dahllite in composition, but contains a notable amount of fluorine.

1 Lacroix, A., Sur la constitution mine'ralogique des phosphorites franchises: Compt. Rend., vol. 150,1910,. 

p. 1213; Mine'ralogie de la Franco, vol. 4, second part, 1910, p. 555.

2 Brogger, W. C., and Backstrom, H., Dahllite, a new mineral from Odegarden, Bamle, Norway: Abstracted in Zeitschr. Kryst. Min., vol. 17,1890, p. 426; also in Dana's system of mineralogy, 6th ed., 1892, 

p. 866.

8 Tschirwinsky, W., Podolite, a new mineral: Centralbl. Min. Geol. Pal., 1907, p. 279. For some earlier 1 

but incomplete descriptions in Russian publication, see abstract thereof in Zeitschr. Kryst. Min., vol. 46, 

1909, p. 296.

4 Lacroix, op. cit. See also the following paper in this volume.

6 Henry, T. H., On francolite, a supposed new mineral: Philos. Mag., vol. 36, 1850, p. 134. The COa 

present in the mineral was not detected by Henry. A better analysis of francolite from Cornwall was later 

given by Story-Maskelyne, N., and Flight, W., Mineralogical notes 3, Francolite, Cornwall: Jour. Chem. 

Soc. (London), vol. 24,1871, p. 3.

6 Stein, C. A., Ueber das Vorkommen von phosphorsauren Kalk in der Lahn- und Dill-gegend mit 

besonderer Beriicksichtigung des Vorkommens bei Stafiel, Amts Limburg: Jahrb. Ver. Naturk. Herzogthum Nassau, vols. 19-20, 1S64-1866, p. 41. Abstracted in Jahrb. Min., 1866, p. 716.

7 Sur I'hydro-apatite, espece min6rale: Annales des mines, vol. 10, 1856, p. 65.

89
90 MINEKALOGICAL NOTES SERIES 2.

(2) The amorphous, perfectly isotropic type is composed of the 

mineral collophanite, which is a hydrous carbonate and phosphate of 

lime, generally free from any appreciable amount of fluorine, but 

rarely containing a small amount (fluocollophanite).

(3) The third type is composed of the following minerals, in 

variable amounts: .

(a.) Dahllite; (6) francolite (var. staffelite); (c) an unknown mineral, similar to 

dahllite and francolite in chemical composition but differing optically from them; 

(d) collophanite. 

This type of phosphorite, composed of an amorphous mineral and 

one or more crystalline minerals, is called quercyite. If the unknown 

mineral ((c) above) is absent, the subtype is called or-quercyite; if 

the unknown mineral is present, the subtype is called /?-quercyite. 

Quercyite is often formed of alternating layers of <*-quercyite and of 

/?-quercyite.

DESCRIPTION OF MINERALS.

DAHLLITE.

Dahllite occurs as fibrous crusts, stalactites, or concretions with a 

radiating or confused fibrous structure, and also in a pure state as 

nodular masses and concretions, some resembling the fungus polypore having formed against the sides of pockets in the phosphorite. 

It is colorless, white, yellow, or greenish, and is transparent in thin 

pieces. The streak is white, and the luster vitreous, dull, silky, 

or slightly greasy in the very pure specimens. The fibrous concretions are very tenacious. The fracture yields a dull white surface, 

sometimes showing a regular fibrous structure, but more often the 

fibers are radiating or intermingled. From the similarity of the 

shape of the nodular masses of dahllite, quercyite, and collophanite, 

the dahllrte may have formed by the dehydration of the quercyite 

or the collophanite.

Optically the mineral is hexagonal, uniaxial, and negative, the 

fibers being elongated parallel to the least index of refraction. It 

shows the helicoidal optical grouping. The birefringence is slightly 

greater than that of apatite. The mean refractive index (n) = 1.625 

approximately; the hardness is 5, and the density ranges from 2.97 

(on confused fibrous masses more or less porous) to 3.053. When 

heated in a closed tube, it decrepitates without fusion, giving off 

water. It is readily soluble in cold dilute acids, with evolution of 

CO2 . The formula is given as 2Ca3 (P04) 2 .CaC03 4H20, but is more 

probably 3Ca3 (P04) 2 .CaCO3 .H2 0. See discussion in the following 

papers in this volume. For analyses see the table at the end of this 

paper.
MINERALOGY OF THE FRENCH PHOSPHATES. . 91 

PBANCOLITE.

Francolite is found as minute hexagonal crystals showing the 

forms c {0001} and ra {1010}. These are tabular, flattened parallel 

to c {0001}, and are generally grouped in rosettes or confused 

masses. More frequently it forms the fibrous variety stafFelite, as 

mammillated fibrous crusts or as very pure spherolites which were 

formerly considered to be apatite. These spherolites occasionally 

show minute crystals, about 1 millimeter in length, with free ends. 

They are colorless, white, yellow, or greenish, with a vitreous luster 

which tarnishes or becomes dull on exposure to air, the specimens 

changing from translucent to opaque. The streak is white.

The hexagonal crystals show a division of the basal section into 

six sectors, each normal to an acute negative bisectrix, the trace of 

the large axial angle being, in each sector, parallel with the prism 

edge. By superposition of biaxial plates the crystals often appear 

uniaxial. The birefringence is, like that of dahllite, 0.004 to 0.005, 

and the mean refractive index (ri) = 1.625 approximately. The 

hardness is 4 to 5, and the density 3.09 to 3.128. In its pyrognostic 

and chemical properties, it is similar to dahllite, except that it shows 

the presence of fluorine. The formula given for it is (CaF) 2Ca8 (P04) 0. 

CaC03 + H20. Analyses are given at the end of this paper.

UNKNOWN MINERAL.

The unknown mineral, mentioned as forming the characteristic 

component of /?-quercyite, has not been found in a pure state, so 

that its chemical composition is not accurately known, but from 

analyses of specimens of /?-quercyite rich in this unknown mineral 

(analyses Nos. 11 and 12 of this paper), its composition is doubtless 

near that of dahllite and francolite. The distinguishing test, however, is its optical character, for it is positive while both dahllite and 

francolite are optically negative. The birefringence of this positive 

mineral is about double that of the negative ones.

COLLOPHANITE.

The amorphous mineral collophanite forms concretionary masses, 

resembling opal or gum, and has a conchoidal fracture. An earthy 

variety is called monite. Some of the nodules or masses are nearly 

transparent, and others are only translucent, but most of them are 

opaque. The nearly transparent kind looks like carnelian stone, 

the others more like enamel. It is colorless, white, yellow, brown, or 

reddish. It has a vitreous luster, a little resinous or earthy in the variety 

monite. It is isotropic. The index of refraction is not constant 

for different specimens. Two different samples gave for sodium light 

the values 1.569, 1.612. The hardness is 4.5, and the density of the
92 MINEBALOGICAL NOTES -SERIES 2.

common variety 2.69-2.82, though that of monite is as low as 2.1. 

One variety is very poor in or entirely free from fluorine; a second 

variety (fluocollophanite) contains fluorine ranging up to an amount, 

in proportion to the P205 content, equal to that present in apatite. 

Its pyrognostic and chemical properties are like those of the crystallized compounds. Collophanite is often impure from admixed substances. It may be distinguished from similar minerals, such as 

opal, by its ready solubility in acids with evolution of C02 , and by 

its P2 05 reaction. The formula given for it is x[C&3 (~PO4) 2 ] or 

z[(CaF) 2Ca8 (PO4) 6] + ^CaCO3 + 2H20. See following papers. Analyses are given at the end of this paper.

QUERCYITE.

The name quercyite is applied to mixtures of the amorphous 

collophanite and the crystalline dahllite, francolite, and the unknown 

mineral. The most common type of the French phosphorites is 

this variable mixture called quercyite. Only a small portion of the 

phosphorites are composed of either collophanite or one of the 

crystallized phosphates. The mixture in quercyite is so intimate 

that it is impossible to separate the constituents mechanically. If 

the crystalline mineral present is optically negative the mixture 

is called or-quercyite; if the unknown mineral (optically positive) 

is present, the mixture is called /^-quercyite. Quercyite is often 

composed of alternating layers of a- and /?-quercyite. Some of the 

layers may be nearly free of any crystalline material when they 

are composed of only collophanite. The density of <*-quercyite is 

2.83 to 2.87, and the mean refractive index about 1:608.

SUMMARY OF PROPERTIES.

This completes the list of minerals forming the French phosphorites. For convenience their chief diagnostic properties, including those of or-quercyite and of fluorapatite, are here tabulated:
MINERALOGY OF THE FEENCH PHOSPHATES. 93

 sI

p

5 

ts

o

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OJ +J '3

03

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incolite.

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94 MINERALOGICAL NOTES SERIES 2. 

CHEMICAL COMPOSITION.

The chemical composition of the minerals and of their mixture 

quercyite can be seen by the analyses given below. They have been 

grouped together in this way in order to render the comparison more 

easy.

1. Original analysis, Bamle, Norway.

Dahllite analyses... 2. Mouillac, Quercy, France.

3. Podolite, crystals, Podolie, Russia.

4. Podolite, crystalline aggregate, Podolie, Russia.

5. Cornwall, England.

Francoliteanalyses... { 6. d'Encourtiech, Ariege, France. 

7. Staffelite, Staff el, Limburg.

-,,,,., , ( 8. Original analysis, Sombrero, Antilles. Collopnanite analyses.< ,-,. .-, , ~, V, '19. Pouzillac, Gard, Ceyennes, France.

(

10. tf-quercyite, Mouillac, Quercy, France.

11. /?-quercyite, Mouillac, Quercy, France.

12. ^-quercyite, Castillo de Belmez, Cordone, Spain.
Analyses of phosphorite minerals.

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

p o

F.................................

CO.................................

Had............................'..

(Al,Fe)20.........................

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

(K,Na)2O............... ...........

Organic ...........................

Si02 (insoluble) ...................

Less 0 for F. ......................

Dahllite.

1

53.00 

38.44

6.29 

1.37

a. 79

1.00

100. 89

2

53.65 

38.40 

Trace. 

5.30 

2.10 

.57

100. 02

3

51.15 

39.04 

.00 

3.90

(?) 

3.04

97. 13

4

51.31 

36.44 

.26 

4.18

(?) 

2.19

1.11

.56

4.87

100. 92 

.11

100. 81

Francolite.

5

54.09 

38.14 

3.34 

2.25 

1.59 

.91

101. 01 

1.41

99.60

6

52.32 

40.00 

3.36 

5.30

.43

101. 41 

1.41

100. 00

5

1

1
THE PROBABLE IDENTITY OF PODOLITE WITH

DAHLLITE.

A comparison of the properties and chemical composition of 

podolite and dahllite shows them to be essentially identical. Dahllite was described in 1888 by Brogger and Backstrom,1 and podolite 

by Tschirwinsky 2 in 1907, and the summary of the properties of the 

two minerals given below has been prepared from the printed 

descriptions.

Properties of dahllite and podolite.

Dahllite.

Occurs in crusts with fibrous structure, 

on apatite.

Density is 3.053.

Color is pale yellowish white.

TJniaxial, negative.

Double refraction and index of refraction 

slightly greater than that of apatite.

Soluble in cold dilute acid with evolution 

of C02 .

Composition |H2Cal4P8C2039 or Composition.. -t2OaJtP808 .OaCO,.iHaO

Podolite.

Occurs in crystalline masses or in prismatic crystals on phosphorite, also in 

spherulites of prismatic crystals.

Density is 3.077.

Color is yellowish.

Apparently hexagonal, crystals show 

optical anomalies, negative.

Double refraction somewhat greater than 

that of apatite.

Mean index of refraction 1.635.

Soluble in HC1 with evolution of C02 . 

10P6C027 or 

!a3P208 -CaC03

To better compare the two formulas, they are given, below with Ca 

given in constant amount.

Dahllite. 

Podolite.

The analyses of the two minerals are shown in the following table 

for comparison:

1 Brogger, W. C., and Backstrom, H., Dahllite, a new mineral from Odegarden, Bamle, Norway. 

Abstracted in Zeitschr. Kryst. Min., vol. 17, 1890, p. 426; also in Dana's System of mineralogy, 6th ed: 

1892, p. 866.

2 Tschirwinsky, W., Podolite, a new mineral: Centralbl. Min., Geol. u. Pal., 1907, p.. 279; abstracted in 

Zeitschr. Kryst.1 Min., vol. 46, 1909, p. 296. .

96
PROBABLE IDENTITY OF PODOLITE WITH DAHLLITE. 

Analyses of dahllite and podolite.

97

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

P O

co2 .. ........................................

H20..........................................

Fe203 . .......................................

A1203.- .......................................

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

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

F. ............................................

Organic .......................................

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

Total....................................

Dahllite.

53.00 

38.44 

6.29 

1.37 

a.79

.ii

.89

100. 89

Podolite.

Crystals.

51.15 

39.04 

3.90 

Not det. 

3.04

.00

97.13

Crystalline 

aggregate.

51.31 

36.44 

4.18 

Not det. 

1.73 

.46 

.45 

.66 

. .26 

.56 

4.87

100.92

«FcO.

The above figures show the undoubted identity of the three substances analyzed. The C02 values for podolite are slightly lower 

than that given for dahllite, but the differences are slight. Water 

was not determined, but it must unquestionably have been present, 

for such a secondary mineral as podolite would be very likely to 

contain some, and a small amount, at least, must have been absorbed 

by the ground sample. The poor summations and the varying values 

in general lead one to suspect that further analyses of purer material, 

carefully made, would lead to slightly different results. 

23590° Bull. 509 12 7
THE COMPOSITION OF THE PHOSPHOKITE MINERALS.

INTRODUCTION.

The previous paper on the mineralogy of the French phosphorite 

deposits contains several analyses of these minerals, which, with 

those already published, furnish sufficient criteria for a determination of their formulas. I have therefore calculated the ratios from 

the different analyses and by averaging them up, have deduced 

formulas for the minerals in question. Below the actual ratios 

obtained, I have given them with CaO taken as 100.

DAHLLITE.

From analyses 1 to 4, given on page 95, the following ratios are 

obtained:

Ratios from dahllite analyses.

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

P O c&::::::::::::::::::::::::::::::::::

H20....... ...........................

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

Pa08 ............. ......................

C02L.................................

H20... ...............................

1

0.945

.271

.143

.076

100

29

15

8

2,

0.956

.270

.120

.117

100

28

13

12

3

0.912

.275

.090

(?)

100

30

10 (?)

4

0. 915

.256

.095

(?)

100

28

10

(?)

The average values of these yield the formula.

lOO(CaO). 29(PA). 12(00,). (10H2 0), 

which is sufficiently close to the simple one

lOCaO. 3P2O5 . C02 . H2 0.

to suggest strongly that this is the correct formula for dahllite.

FRANCOLITE.

From analyses 5 to 7, given on page 95, the ratios shown below are 

deduced: 

98
COMPOSITION OF THE PHOSPHOKITE MINEBALS. 99 

' Ratios from francolite analyses.

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

P F2O 05 ... .........................................

C0a . . ......... ...... ......... ...... ...... ... .

H20........ .....................................

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

PA- O ..

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

HaO......... ....... ...... .. ...... 

 5

0.964

.269

.176

.051

.088

100

28

18

5

9

6

0.933

.282

.177

.084

.088

100

30

1Q

q

q

7

0 974

.275

.161

079

.078

100

28

17

8

8

The average of these values gives 

lOO(CaO). 29(P2O5). 18(F). 7(CO2). 9(H2 0)[minus 9O], 

which reduces to the simpler formula

10(CaO). 3(P2 05) 2(F). (CO,). (H2 0) [minus 10], 

which may be written

9CaO. 3P2Q5 . C02 . H2 0. CaF2 .

The average ratio of P2 05 to CaO is 3 to 10.44, being for analysis 

No. 5, 3 to 10.75; for analysis No. 6, 3 to 9.93; and for analysis No. 

7, 3 to 10.63. This value lies almost exactly halfway between the 

3:10 ratio required by my formula above and the 3:11 required 

by Lacroix's formula for francolite.

COLLOPHANITE.

From the values given in analyses 8 and 9, on page 95, the following ratios are deduced:

Ratios from collophanite analyses.

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

p n

F.........................................................

CO

HjjO................................................. ........

CaO....................................................... PA------- 

F.........................................................

coa .......................... ...............................

ILaO............. ...........................................

8

0.904

.275

.090

.279

100

30

10

31

9

0.886

.263

.046

.085

.392

100

30

5

10

44
100 MINERALOGICAL NOTES SERIES 2.

The average formula developed is

lOCaO. 3P2 05 .CO2 . 3+ H2O(+F?). 

SUMMARY.

The three formulas developed are repeated here in order to show 

their relation to one another. To the list are added those of apatite, 

both the fluoapatite and the hypothetical hydroxyapatite.

Dahllite.......... 9Ca0.3P205 .CaO. C02 .H20.

Francolite......... 9Ca0.3P2 05 .CaF2 .C02 .H20.

Collophanite. - -... 9Ca0.3P2 05 .CaO. C02 .H20+nH20. 

Fluoapatite ....... 9Ca0.3P2 05 .CaF2 .

Hydroxyapatite... 9Ca0.3P205 .CaO. H20.

The derivation of dahllite from the dehydration of collophanite 

becomes very simple, proceeding according to the reaction,

9CaO.3P2 05 .CaO.C02 .H2 0. ILO = 9CaO.3P2 05 .CaO.C02 .H2 0 4- 7iH2O. 

(Collophanite) 'Dahllite')

By the introduction of fluorine, the reaction would yield francolite 

instead of dahllite:

9CaO.3P2 05 .CaO.C02 .H2 0.nH2O + 2HF =

(Collophanite) 9CaO.3P2 05 .CaF2 .C02 .H2 0 + nH2 0.

(Francolite)
NATRAMBLYGONITE FROM COLORADO. 

OCCURRENCE.

The mineral described in this paper was collected by me in 1908 in a 

large pegmatite mass 4 miles northwest of Canon City, Colo. The 

presence of lithium minerals lepidolite and pink tourmaline had been 

noted in this pegmatite by Sterrett 1 and it was through his kindness 

and that of Mr. J. D. Endicott, of Canon City, that I was enabled to 

visit the locality and collect a suite of specimens from the pegmatite. 

As described by Sterrett, the tourmaline and associated minerals occur 

on a low, oval hill composed of pegmatite inclosed in contorted biotite 

and hornblende gneiss. Pink tourmaline and lepidolite are abundant, 

though no cavities or pockets affording gem tourmaline were seen, the 

mineral being found only in the solid pegmatite.

ASSOCIATION.

The minerals associated with natramblygonite are few in number 

and do not possess any unusual properties. Tourmaline is abundant 

in black, pink, or green crystals, though no faces except those in the 

prism zone were seen on any of the crystals collected. A dark-green, 

nearly black core with a pink shell seems to be a common color association for this locality. Small masses of minute bluish crystals, and 

some larger green ones embedded in muscovite, were also noted. 

Most of the tourmaline is opaque and partly altered. The micas, 

muscovite and lepidolite, are also abundant. Lepidolite occurs in 

scaly pink masses, also as larger plates and in indefinite crystalline 

aggregates of pink or purplish colors. Albite generally is tabular in 

platy masses or in groupings of small crystals. , The quartz and potash 

feldspars are massive and the original piece of natramblygonite, now 

deposited in the United States National Museum, is also massive. 

The mineral has recently been found in well-developed crystals.

DESCRIPTION OF MINERAL.

The specimen of the mineral measures about 5 by 7 by 3 centimeters and consists of a mass of cleavable natramblygonite surrounded by feldspar and lepidolite. Small veins and isolated masses 

of lepidolite are scattered through the new mineral. Small amounts 

of pink tourmaline and of albite were also detected embedded therein.

Three directions of cleavage can be detected, one more prominent 

than the other two. A section of the mineral cut parallel to the most 

prominent cleavage showed the other two cleavages intersecting at

1 Sterrett, D. B., The production of precious stones in 1908: Mineral Resources United States for 1908, 

U. S. Geol. Survey, 1909, p. 44.

101
102 MINERALOGICAL NOTES SERIES 2.

about 70°. In its general appearance the mineral resembles massive 

amblygonite very much. The hardness is 5.5, and determinations of 

the specific gravity varied from 3.01 to 3.06, with an average value 

of about 3.04. The luster is vitreous, inclining slightly to greasy. 

The color is grayish white to white. In the hand specimen it is 

translucent to opaque.

Examined in thin section under the microscope, inclusions of quartz, 

feldspar, and mica can be seen, and also an irregular distribution of a 

kaolin-like dust. Two directions of polysynthetic twinning lamellae 

intersecting at about 86° are prominent, and lie at an angle against 

the cleavage cracks. The best cleavage is nearly normal to a bisectrix, and the section parallel to this cleavage shows a biaxial interference figure with a large angle. The optical sign of the mineral is 

negative. Its mean refractive index lies near 1.60.

Heated in a blowpipe flame the mineral easily fuses, without 

decrepitation but with slight intumescence to an opaque white enamel, 

The flame is yellow with no indication of the red characteristic of 

lithium. In this particular natramblygonite differs markedly from 

amblygonite, and can thereby be distinguished from the common 

mineral. It would be well to test amblygonite from different localities 

by this flame test. Heated in a closed tube, water is given off and the 

mineral then quietly fuses without decrenitation to a blebby enamel 

firmly fused to the glass tube.

CHEMICAL COMPOSITION.

Analysis of a selected sample of natramblygonite gave the values 

shown below. The sample was finely crushed, and all visible impurities and doubtful pieces picked out by hand under a magnifying glass. 

All of the final sample sank in a Thoulet solution of density 3.01 + 

and floated in solution of density 3.06. Beryllium was tested for but 

could not be detected. The mineral is difficultly soluble in H2SO4 , in 

which solution no calcium could be found.

Analysis and ratios of natramblygonite.

P O

AljOa .. - - 

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

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

K20.. ..........................::.............

H2 0+...................... ...................

F.......................... ....................

Less 0 for F. ...................................

Per cent.

44.35

33.59

3.21

11.23

.14

4.78

5.63

102. 93

2.37

100. 56

Rati

0.312

.329

.107

.181

.001

.266

.296

0.

1.00

1.06

.93

.851-. oo

. 47/1' ^
NATRAMBLYGONITE FROM COLORADO. 103

The ratios yield the formula P205 .Al2 03 .(Na,Li) 2 0.(H20,F2 ) which 

may be written more simply AlNa(OH)P04 , with the Na partly 

replaced by Li and the (OH) by F. The ratios for water and fluorine 

are a little high, probably due to the difficulty of the fluorine determination. It is worthy of note, however, that the ratios for water 

and fluorine are all high in Penfield's analyses of amblygonite. 1 The 

relations of natramblygonite to amblygonite are clear, the first being 

essentially the sodium mineral and the second the lithium one:

Natramblygonite, Na[Al(OH,F)]P04 . 

Amblygonite, Li[Al(OH,F)]P04 .

Nothing was seen which would indicate that the new mineral here 

described was originally the lithium compound and was afterward 

changed to the sodium one. The alteration of amblygonite, described 

by Carnot and Lacroix,2 yielded the mineral morinite, which contains 

lime and soda, without any lithia, and much more water and fluorine 

than was present in the amblygonite.

1 PenfleW, S.L., On the chemical composition of amblygonite: Am. Jour. Sci., 3d ser., vol. 18,1879, pp. 295.

2 Carnot, A., and Lacroix, A., The chemical composition of morinite: Bull. Soc. franc. min6ralog.. vol. 31, 

1908, p. 149.
THE PROPERTIES OF MOSESITE. 

GENERAL DESCRIPTION.

The name mosesite was proposed by Canfield, Hillebrand, and 

Schaller, for a mercury mineral, described by them, 1 from Texas, in 

honor of Prof. Alfred J. Moses, of Columbia University, New York, 

who first definitely described the interesting mercury minerals at 

Terlingua, Brewster County, Tex.

In the general description of the mineral Mr. Canfield states that 

the small yellow crystals, associated with montroydite, were perched 

on calcite crystals, on which they appeared to lie with but little or no 

bond. The slightest touch would loosen them, leaving no scar upon 

the calcite, but merely a clean spot. A careful search revealed 26 

crystals, 22 of which are simple octahedrons and the others spinel 

twins. No other forms were observed, and none of the mineral was 

massive. A second specimen showed hundreds of crystals scattered 

over a surface of calcite measuring 4 by 6 centimeters, which rests 

upon the pinkish rock characteristic of the Terlingua specimens. 

Canfield gives the following description of these crystals:

Nearly all of the crystals are spinel twins. They are frequently grouped together 

in confused masses; one polysynthetic twin a 5-ling was seen. Simple octahedrons 

are rare. None was modified by other forms. No other mercury mineral is present in 

the specimen unless some delicate, elongated, light-yellow particles should prove to 

be kleinite.

There are no indications that the crystals are affected by the light. If light affects 

the color, it must act very slowly. The color of those crystals which are so situated 

as to have some protection from the light is exactly like that of the most exposed. No 

difference in color could be noted between the surface and the interior of the crystals.

Most of the crystals are translucent. The largest crystal found is brilliant and transparent and measures 0.5 millimeters along its edge. Generally the faces of the crystals 

are bright and uneven. They are very brittle, with signs of cleavage. 2 The fracture is 

uneven. The hardness slightly exceeds that of calcite. The mineral crumbles to 

a powder under the pressure required for this test. No piece could be obtained that 

.was large enough to determine the density. The luster is adamantine. The color is 

a rich lemon to a canary yellow. The streak and powder are a very pale yellow.

CHEMICAL, PROPERTIES.

Mr. Canfield gives the following description of the chemical properties 

of the mineral:

When heated gradually to a low temperature in a closed tube, the assay turns to 

a dark reddish brown, almost black. As the heat increases the color changes rapidly

1 Canfield, F. A., Hillebrand, W. F., and Schaller, W. T., Mosesite, a new mercury mineral from Terlingua, Tex.: Am. Jour. Sci., 4th ser., vol. 30,1910, pp. 202-208.

2 The cleavage is imperfect octahedral. Schaller.

104
PEOPEETIES OF MOSESITE. 105

to white, but without changing the form of the original crystals. Fumes of calomel 

are given off and condense in the tube. Many globules of mercury collect in the tube 

beyond the coating of calomel. Continued heating soon causes the assay to volatilize 

and disappear. If a fresh fragment of the mineral is heated rapidly in the closed tube 

it decrepitates violently, almost explosively, then it fuses and volatilizes.

In cold hydrochloric acid the mineral is changed slowly to a white substance, which 

retains the original form. If the acid is hot, the change is more rapid but the product 

is the same.

Dr. W. F. Hillebrand examined the material chemically and found 

that 

So far as the very scanty material permitted of ascertaining, the composition of 

moseeite approaches that of kleinite; that is, it is a mercury-ammonium compound containing chlorine and the sulphate group besides a little water. Determinations made 

on 0.04 gram of material gave 5 per cent Cl and 3.5 per cent S04 . The former amount 

is considerably lower and the latter somewhat higher than in kleinite, but the values 

are no more than approximations. There is, however, one marked chemical difference, which will be considered later.

Spectroscopic tests that were kindly made by Dr. P. G. Nutting, at the Bureau of 

Standards, showed prominent mercury and nitrogen spectra and also the red line of 

hydrogen, the last being ascribed by him to water vapor. A singular feature of the 

behavior in vacuo was the immediate appearance, when the current was turned on 

and before the application of heat, of a mercury spectrum.

The mineral was at the time not between the electrodes, but far to the rear of one of 

them, at the sealed end of the Plucker tube. Under these conditions the color of the 

mineral fragments underwent a pronounced and permanent change from bright 

yellow to a yellowish gray. With a minute crystal of kleinite there was a mere indication of the mercury lines before heating, and no color change was observed. As soon 

as the temperature of mosesite was raised to visible incipient decomposition, the spectra 

of both nitrogen and mercury became brilliant. As mentioned by Mr. Canfield, 

mosesite does not seem to undergo the color changes in sunlight and darkness that appear 

to be characteristic of the deeper-colored crystals of kleinite.

When heated in a narrow tube closed at one end, the color changes and the sublimates were much like those afforded by kleinite, and there was the same liberation 

of an active gas that set free iodine from potassium iodide. Ammonium bromide 

liberated ammonia as from kleinite.

The behavior toward hydrochloric acid, noticed by Mr. Canfield, affords a certain 

chemical means of distinguishing mosesite from kleinite where only these two are 

concerned. When covered with concentrated hydrochloric acid mosesite is entirely 

decomposed in a few hours, with separation of a coherent white material that shows 

the behavior of calomel. The solution contains the sulphate and ammonium groups, 

besides much mercuric mercury. Kleinite, on the other hand, shows no perceptible 

change for a long time, but in the course of 48 hours a minute crystal of it was almost 

entirely decomposed. There remained only a whitish residue that looked as if it 

might be the claylike matter that is such a persistent contaminant of the mineral. 

It was free from calomel.

It will be remembered that the chemical evidence points to kleinite being a mixture or solution of mercury-ammonium chloride with a mercuric sulphate and perhaps 

chloride. There would seem to be an association of similar general character in 

mosesite, but with a mercurous sulphate or chloride replacing in part or wholly the 

corresponding mercuric salts of kleinite.
106 MIETEKALOGICAL NOTES SEBIES 2. 

CRYSTALLOGRAPHY.

In studying the crystallography and optical properties of mosesite, 

I found that the crystals are apparently octahedra of the isometric 

system. Twinning on the spinel law has been observed several 

times; when this occurs, the crystals of mosesite are very commonly 

flattened parallel to a pair of octahedral faces. Mr. Canfield has 

mentioned a 5-ling, a spinal twin repeated five times.

The faces of the crystals are never smooth. Though bright and 

often highly polished, they are uneven, and only a few of the faces 

give a single reflection. Most of the faces when measured on the goniometer give a number of signals, no particular one of which is brighter 

than the others. This condition has rendered accurate determination 

of the form of the crystals impossible. An additional feature that 

has rendered accurate measurements difficult is the tendency for a 

number of crystals to grow together, some in nearly parallel position 

and others at widely different angles. A mass of signals, therefore, 

resulted from examining such groups of mosesite on the goniometer, 

and on the minute crystals that were available it was not possible 

to know what signals to measure and what ones to exclude. Where 

only two or three faces were measured in a zone, it was well-nigh 

impossible to be sure of having the zone accurately centered. The 

measurements, the occurrence of (probable) spineltwins, and the 

optical relations about to be described make it fairly certain that the 

crystals of mosesite are in reality octahedra. No form other than 

the octahedron was observed.

On part of a spinel twin, the faces of which gave a mass of very 

poor reflections, there were measured:

=68°............................................ 70° 32' calculated.

o/\0' =68° (cleavage face).............................. 70° 32' calculated.

=6&° 28'.......................................... 70° 32/ calculated.

o/\o =41° 13'.......................................... 38° 56' calculated.

A second crystal, also a spinel twin, gave:

oAc/

=108° 54'........................................ 109° 28' calculated.

=107° 53'........................................ 109° 28'calculated.

= 71° 38'........................................ 70° 32'calculated.

= 70° 47'........................................ 70° 32' calculated.

= 68° 51'..........................-:....... .... 70° 32'calculated.

= 72° 28'........................................ 70° 32'calculated.

= 37° 06'......................................... 38° 56'calculated.

= 38° 56'........................................ 38° 56'calculated.

A third crystal was adjusted as closely as possible in polar position 

for two-circle measurement and on revolving the crystal, the four 

octahedral faces were seen to lie in the positions required for the form 

{111}.
PROPERTIES OF MOSESITE. 107

From the above data, meager and poor as they are, the isometric 

character of the crystals is deduced, especially as this is supported 

by the investigation of the optical properties.

OPTICAL PROPERTIES.

Under the microscope mosesite is pale yellow, nonpleochroic, and 

seems to possess a moderate double refraction. When a fragment 

is crushed many of the resultant pieces have a triangular or rhombic 

shape, due to the octahedial cleavage. When a fragment of fluorite 

was crushed and examined under the microscope similar effects were 

seen, though the cleavage was much better developed.

The crystallographic measurements have shown that the crystals 

are in all probability isometric octahedra and should, therefore, be 

isotropic when examined under the microscope with crossed nicols. 

Such an examination, however, shows the mineral not to be isotropic,

but doubly refracting. On heating the mineral to 186°, the crystals 

lose their double refraction and become isotropic. Mosesite is therefore dimorphic, the isometric optical condition that agrees with the 

geometrical form being stable only above 186°, the mineral changing 

to the dimorphous doubly refracting condition at temperatures 

belpw 186°.

As examined at ordinary temperatures, the sections show great 

similarity to kleinite. , Much of the material does not extinguish at 

all; other parts extinguish four times during a complete revolution 

of the stage, and the interference colors are brilliant. On crushing 

a fragment between two glass slides and examining the very small 

particles, they are seen to be nearly colorless, and, unlike the larger 

pieces, isotropic. It seems that the local heat developed by the 

crushing is sufficient to heat these small particles to at least 186° 

and cause their reversion to the isotropic state.

Seven different fragments were heated on glass slides in an air 

oven to the temperatures given and with the results shown in the 

following table:

Effect of heating mosesite.

No. of 

slide.

1

3

Tempera- 

, ture.

/ 150 

\ 200

160

167

180

189

169

190

Effect.

No change; mineral still doubly refracting. 

Brown and isotropic.

Brown and doubly refracting.

Doubly refracting.

Doubly refracting.

Isotropic.

Doubly refracting, but section too opaque for

further study.

Probable temperature of

change.

150-200°.

180-189°.

Above 169°.
108 MINERALOGICAL NOTES SERIES 2. 

Effect of heating mosesite Continued.

No. of 

slide.

4

6

7

Temperature.

f 169

184

i 186

[ 190

f 184

186

188

190

/ 186 

1 192

( 186

I 192

Effect.

Doubly refracting.

Doubly refracting.

Nearly isotropic.

Isotropic.

Doubly refracting.

Nearly isotropic.

Nearly isotropic.

Isotropic, except for a few minute doubly

refracting spots.

Doubly refracting. 

Still doubly refracting in places, but partly

isotropic. This particular piece may have

been thicker than the others, and therefore

did not revert so readily.

Isotropic on thin edges, but doubly refracting 

in thicker center.

Isotropic.

Probable temperature of 

change.

186-190°.

184-186°.

186-192°+.

186-192°.

From these data the temperature of reversion to the isotropic 

isometric state probably lies between 180° and 190° and is taken as 

186°. If the "molecular inertia" of mosesite is considerable, as is 

the case with kleinite, 1 then this temperature, 186°, is probably a 

little high. On cooling, the isotropic mineral does not immediately 

again become doubly refracting. Examination after 24 hours shows 

the mineral to be still isotropic. The change back seems to be, like 

that of kleinite, a very slow one, but doubtless it is gradually taking 

place. A section of kleinite described by Hillebrand and Schaller 2

as almost entirely reverted after 30 months is now, after 4 years, 

completely changed back to its original doubly refracting condition. 

The optical similarities shown by these two minerals, coupled with 

their evident chemical relationship, suggested trying the effect of 

heating kleinite to the reversion temperature of mosesite (186°). 

When this was done, kleinite 3 became optically isotropic, like mosesite. 

The results of the experiments are shown in the table below:

1 Hillebrand, W. F., and Schaller, W. T., The mercury minerals from Terlingua, Tex.: Bull. U. S. Geol. 

Survey No. 405,1909, p. 26.

2 Idem, p. 25.

8 Fragments were used that were not parallel to the base, as these would become isotropic at 130°, 

kleinite being uniaxlal, hexagonal.
PROPERTIES OF MOSESITE. 

Effect of heating Ideinite.

109

No. of

slide.

1

O^

3

Temperature.

\ 177

187

I 194

/ 177

\ 194

/ 177 

\ 194

Effect.

Doubly refracting; no change.

 Doubly refracting; no change.

Doubly refracting; no change. Probably too thick.

Doubly refracting; no change.

Isotropic.

Doubly refracting; no change. 

Partly isotropic, the remainder doubly refracting as before.

The isotropic part, while still transparent, had become

brown, the doubly refracting part remaining pale yellow.

It would be premature to speculate on the significance of this 

observation on the optical behavior of kleinite.
THAUMASITE FROM BEAVER COUNTY, UTAH. 

INTRODUCTION.

The interesting mineral thaumasite was first described in 1878 by 

Baron von Nordenskiold 1 from material collected at the copper mines 

of Areskuta, Jemtland, Sweden. Since that time it has been noted 

from other localities in Sweden, and in 1896 it was described by 

S. L. Penfield and J. H. Pratt from Berger's quarry, West Paterson, 

N. J.

Dr. Edgar T. Wherry, of Lehigh University, has been kind enough 

to call my attention to a second New Jersey locality for thaumasite. 

Dr. Wherry writes:

During the past few years, however, it has been found in considerable amount at 

another place in the same region, but sufficiently distant to be worth distinguishing 

Francisco Bros.' quarry at Great Notch, 3 miles southwest of Paterson. It has been 

taken so as a matter of course that it should be found there, that nobody appears to 

have taken the trouble to call particular attention to it, and I can only find two published references, both in out-of-the-way places:

Papke, Hermann, A visit to the mineral localities at Paterson and Great Notch, N. J. : 

Mineral Collector (N. Y.), October 15,1908, p. 118.

Levison, W. G., On the origin and sequences of the minerals of the Newark (Triassic) 

igneous rocks of New Jersey: Bull. New York Mineralog. Club No. 2, Dec., 1909, 

p. 23.

During the summer of 1909, Mr. B. S. Butler, while engaged in a 

geologic survey of the Frisco district, Beaver County, Utah, found 

a mineral of unusual appearance which on examination in the office 

proved to be thaumasite. The mineral was found in the old Hickory 

mine of the Majestic Copper Co., located in the Rocky Range, Rocky 

district, Beaver County, Utah, about 4 miles northwest of the town 

of Milford, which is on the San Pedro, Los Angeles & Salt Lake 

Railroad.

GEOLOGIC OCCURRENCE.

Mr. Butler describes the geologic occurrence as follows: 2

The Rocky Range is composed at the southern end, where the mine is located, of a 

series of interbedded dolomitic limestones and quartzites of probable Carboniferous

» Compt. Rend., vol. 87,1878, p. 313.

2 Butler, B. S., and Schaller, W. T., Thaumasite from Beaver County, Utah: Am. Jour. Sci., 4th ser.f 

vol. 31,1911, pp. 131-134.

no
THAUMASITE FROM BEAVER COUNTY, UTAH. Ill

age which have been intruded by monzonite. The intrusion of the monzonite has 

produced typical contact alteration of the limestone, resulting in the formation of 

magnetite, garnet, and pyroxene, with some pyrite and chalcopyrite. At the Old 

Hickory mine the limestone for several feet from the contact has been largely replaced 

by magnetite with a small percentage of the contact silicates and sulphides of iron and 

copper. As the distance from the contact increases the amount of magnetite decreases and the contact silicates become correspondingly more abundant, and these in 

turn give place to the carbonates composing the limestone. The zone of magnetite 

carrying copper values as chalcopyrite and secondary alterations of this mineral (covellite, chalcocite, and copper carbonate) has furnished the ore that has been shipped from 

the mine. In the general vicinity of the mine, and especially to the north and northwest, there are veins from a fraction of an inch to upward of a foot in width, composed 

of a dense white material with conchoidal fracture that on analysis proved to be 

composed largely of magnesium carbonate with some calcium carbonate. These 

magnesite veins, however, were not observed in the Old Hickory mine.

The Old Hickory mine has been developed to a depth of about 300 feet and four 

levels have been opened. A vertical shaft extends to the lowest level, while the 

second level, about 100 feet deep at the shaft, is connected with the surface by a tunnel.

The first level is about 80 feet below the surface and about 20 feet above the tunnel 

. le'vel. On the first level the magnetite body has been opened for a distance along the 

strike of about 125 feet. To the east of this, a distance of from 10 to 25 feet from the 

magnetite body, a parallel drift has been run in the altered limestone. One hundred 

feet south of the shaft a crosscut from this drift extends to the east about 25 feet, where it 

encounters quartzite. Throughout this eastern drift and crosscut are a great number 

of veins of white material varying from the thickness of paper to upwards of two 

inches. To the north of the crosscut many of the veins are open, the crystals projecting into the openings, while others are composed of a dense white substance. The 

material from these veins proved on examination to be a mixture of quartz and carbonate, the latter probably largely calcite. In the east crosscut, just east of the drift 

and extending across the drift to a crosscut on the opposite side, is a zone of veins having 

a general northeast-southwest direction, though the individual veins vary in direction and are connected by crossveins, making a network. These are composed of 

thaumasite completely filling the fissures.

The fissuring occurred later than the contact metamorphism of the limestone, and 

the filling of the fissures with thaumasite of course occurred at a still later period. 

The thaumasite was not found associated with the quartz and carbonates in the same 

veins, and the relative age of the minerals was not determined. At the Paterson 

occurrence the thaumasite is in trap, associated with heulandite, apophyllite, laumantite,. pectolite, chabazite, scolecite, and natrolite, the thaumasite crystallizing 

later than the zeolites. No zeolites were found associated with the thaumasite at the 

Old Hickory mine, though these were especially looked for. It seems probable, 

however, that the mineral was found under physical conditions similar to those 

favorable to the formation of zeolites.

PHYSICAL CHARACTER.

In the hand specimen the thaumasite from Beaver County is a 

nearly pure white mineral with a silky luster due to its fibrous character. It is readily recognized in the field as an unusual mineral by its 

luster and low specific gravity (1.84). Under the microscope it is 

seen to be composed of minute slender prisms, none of which showed
112 MINERALOGICAL NOTES SEEIES 2.

any terminal faces. Microscopically it is most readily distinguished 

by its low index of refraction and rather high double refraction; 

a) = 1.507, e = 1.468 as determined by LeVy and Lacroix. The indices 

of refraction for the Beaver County occurrence were approximately 

determined by Butler by immersion in solutions of known index 

as a) = 1 .500 +, e = 1.464 +. The mineral extinguishes parallel to the 

elongation of the prisms and is probably hexagonal, as it has been 

found to be in the previously described occurrences. Crystals suitable for measurement and careful determination of the refractive 

indices were not found.

CHEMICAL COMPOSITION.

A determination of the density of the thaumasite by means of the 

Joly balance gave the value 1.84. A second determination, using the 

Thoulet solution and small fragments of the mineral, gave the value 

1.85. These figures are slightly lower than those found by Penfield 

(1.88) on the New Jersey thaumasite.

The analyses of the Utah thaumasite, with the ratios deduced 

therefrom, are shown below:

Analyses and ratios of thaumasite, Utah.

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

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

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

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

H^O... .......................................

(M,Fe)203 ..... ...............................

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

Afc.,P205 . ....................................

Per cent.

10.14

12.60

6.98

26.81

42.97

.20

.23

Trace.

99.93

0.169

.156

.159

.479

2.387

.002

« .006

Ratio.

1.06

98

1.00

3.00

14.95

1

1

1

3

15

The ratios agree very closely with the established formula 

3CaO.Si02 .SO3 .CO2 .15H2O, and the mineral is very pure, only a trace 

of some foreign matter probably a silicate being present.

A comparison of the analyses of the mineral from Utah, from New 

Jersey, and from Sweden (the average of the three original analyses 

given by Lindstrom) strikingly shows the uniform composition of 

this rare mineral.
THAUMASITE FROM BEAVER COUNTY, UTAH. 

Comparison of analyses of thaumasite.

113

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

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

C0a ......... ....... ....................

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

H20..................................

(Al,Fe)203 . ...........................

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

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

v c\

P O &°":::::v:::::::::::::::::::::::::::

Jemtland, 

Sweden.

Q 70

iq 09

6.86

27.28

4? 20

.16

.11

AC

.12

99.53

New 

Jersey.

9.26

13.44

6.82

27.13

42.77

.39

TO

99.99

Utah.

10.14

12.60

6.98

26.81

42.97

.20

.23

} Trace.

Trace.

99.93

Theoretical composition.

9.64

12.86

7.08

27.01

43.41

100. 00

The new locality in Utah makes the third general locality in which 

this mineral has been found, or the fifth distinct mine, the three 

localities in Sweden being fairly close together.

BIBLIOGRAPHY.

Backstrom, H., Geol. For. Forh., vol. 19, 1897, p. 307.

Bertrand, E., Bull. soc. mineral., vol. 3,1880, P- 159; vol. 4, 1881, p. 8; vol. 19, 

1896, p. 88. Geol. For. Forh., vol. 9, 1887, p. 131.

Butler, B. S., and Schaller, W. T-, Am. Jour. Sci., 4th ser., vol. 31,1911, p. 131.

Cohen, E., Jahrb. Mineral., vol. 2, 1881, p. 22.

Lacroix, A., Geol. For. Forh., vol. 9, 1887, p. 35.

Levy, A. M., and Lacroix, A., Mine"ralogie des roches, 1888, p. 286.

Lindstrom, G., Oefv. Ak. Stockholm, vol. 35 (No. 9), 1878, p. 43.

Nordenskiold, A. E., Compt. Rend., vol. 57, 1878, p. 313. Geol. For. Forh., vol. 5, 

1880, p. 270; vol. 8,1886, p. 146.

Penfield, S. L., and Pratt, J. H., Am. Jour. Sci., 4th ser., vol. 1, 1896, p. 229.

Pisani, F., Bull. soc. mineral., vol. 19, 1896, p. 85.

Widman, 0., Geol. For. Forh., vol. 12, 1890, p. 20.

Zambonini, F., Mem. Ace. Sci. Napoli, vol. 14, 1908, p. 11. 

23590° Bull. 509 12 8
THE IDENTITY OF STELZNERITE WITH ANTLERITE.

Stelznerite was described as a basic copper sulphate by Arzruni 

and Thadde'eff 1 in 1899, their paper being edited by A. Dannenberg 

on account of the death of Arzruni. Prof. F. W. Clarke has recently 

called my attention to the chemical identity of stelznerite with a 

mineral- analyzed by Dr. W. F. Hillebrand and named antlerite;2 

I have extended the investigation by examining optically some of 

the original type material in the U. S. National Museum, for which 

privilege I wish to acknowledge the kindness of the assistant curator, 

Dr. J. E. Pogue. All the facts ascertained point to the identity of 

stelznerite with antlerite.

Antlerite, under the microscope, was seen to consist of a homogeneous aggregate of very minute crystals of short prismatic habit 

and of pale greenish color. The crystals extinguished parallel but 

were too small for any determination of their optical orientation. 

The small crystals were not perceptibly pleochroic, but on the thicker 

ones a decided pleochroism was noticed, identical with that described 

for stelznerite.

Parallel to the elongation of the crystals, the color was blue green; 

normal thereto the color was yellow green. The double refraction is 

high. These data are all in accord with those given for stelznerite. 

The values of the density, 3.93 (antlerite) and 3.884 (stelznerite, not 

corrected for admixed gypsum) agree closely,

Chemically the two minerals are also seen to be identical, as was 

first noted by Prof. Clarke. The formula deduced for stelznerite is 

3CuO.S03 .2H20, or CuS04 .2Cu(OH) 2i while Hillebrand calculated the 

more complex one, 10Cu0.3S03 .7H20, or 3CuS04 + 7Cu(OH) 2 , for 

antlerite. The analyses of antlerite are compared with those of 

stelznerite in the table below. Nos. 1 and 2 are Hillebrand's analysis 

of antlerite, with 8 and 6 per cent, respectively, of gangue deducted, 

and Nos. 3 and 4 are the analyses of stelznerite. The fifth column 

gives the calculated composition for the formula 3Cu0.lS03 .2H2O 

and the sixth that for the more complicated formula 10Cu0.3S03 .7H20.

1 Arzruni, A., and Thaddfiefi, K., Neue Minerale aus Chile; Stelznerit, ein neues basisches Kupfersulfat: 

Zeitschr. Kryst. Min., vol. 31,1899, p. 229.

2 Hillebrand, W. F., Mineralogical notes; 6. A basic cupric sulphate: Bull. U. S. Geol. Survey No. 55, 

1889, pp. 48-54. Also given in Dana's System of mineralogy, 6th ed., 1892, p. 928.

114
IDENTITY OF STELZNEEITE WITH ANTLERITE. 115 

Analyses and calculated compositions ofantlerite and stclznerite.

»

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

so......... ......

H20.............

ZnO.. ............

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

Fe203 -------------

Residue .........

Moisture .........

Antlerite.

1

68.19 

20.46 

11.11 

.29 

.05

100. 10

2

67.64 

21.49 

10.76 

.04 

.04

99.97

Stelznerite

3

67.08 

22.40 

10.22

.06 

.34 

.44

100. 54

4

64. 01 

22.19 

10.37

.57 

1.14 

1.42 

.33

100. 03

3CuO.S03 . 

2H20.

(Calculated.)

67.22 

22.61 

10.17

100. 00

lOCuO. 

3S03,7H20.

(Calculated.)

68.45 

20.69 

10.86

100. 00

Though the first analysis of antlerite agrees better with the more 

complex formula, the second analysis agrees as well with the simpler 

Stelznerite formula. As no certain differences could be found in the 

optical properties. and as the analyses agree so closely with one 

another, the two minerals Stelznerite and antlerite must be considered identical.

The characterization given Stelznerite is much more complete than 

that of antlerite, and the formula deduced, CuS04 .2Cu(OH) 2 , is also 

simpler and is doubtless the correct one for the species. The name 

antlerite has, however, priority by 10 years, and is the one to be 

adopted.

On careful investigation antlerite will doubtless be found to be 

much more abundant than is now thought, and much of what is 

now called brochantite may be found, on analysis, to be the closely 

related antlerite. The artificial brochantite, described by Dana, 1 is 

more likely antlerite.

» Dana, E. S., System of Mineralogy, 1892, p. 920.

o