DEPARTMENT OF THE INTBKIOB

BULLETIN

UNITED STATES

GEOLOGICAL SURVEY

ISTo. ISO

SERIES A, ECONOMIC GEOLOGY, I I

WASHING-TON

GOVERNMENT PKINTING OFFICE 

1901

UNITED STATES GEOLOGICAL SURVEY

CHARLES J). WALCOTT, DIRECTOR

THE

OCCUIIRENCE AND DISTRIBUTION

CORUNDUM IN THE UNITED STATES

BY

JOSEPI-I HYDE PR.ATT

WASHINGTON

G O V JO K N M K N T I' U I M" T I N G O F F I C K 

1 \) 0 1

CONTENTS.

Pfige.

Introduction ..................................................... r ......... 9

Modes of occurrence of corundum ...... ................,_................ U

Corundum in peridotites...._ ..... ............ ..................... 1.1

Corundum in biotite, contact on saxonite .............................. 19

Corundum in enstatite. ................................................1. 20

Corundum in serpentine . _.........._....__...........__....-_..--.._.. 20

Corundum in chlorite-schist............... .... ....... ................... 21

Corundum in amphibolite ................................. ........ 21

Corundum (emery) in amphibolite at Chester, Mass......._.--... .. 23

Origin of the emery.....................!.. .................... 25

Corundum in norite .........,........,.....---------.......-...--..-. 26

Corundum in basic minette... _.._...__._ .__.__.._._. .._:__..----_...__. 28

Corundum in andesite............,.........._..............-......... 29

Corundum in syenite ..... ............._..........................,.... 80

Corundum in ampbibole-schist..-.-.'.....,...-.---..-....-......--..... 31

Corundum in gneiss. .........^.....................'. .......^......... 33

Corundum in mica-schist....... .____......___-...__ .,__.__..._......___. 34

Corundum in limestone ........................--.............._..... 36

Corundum in cyanite............................ ..................... 30

Summary of corundum occurrences...... ....... .................... 37

Distribution of corundum .................................................. 37

Sapphire or corundum gems ....... ..-....................._......... 38

Oriental ruby .........--...........'-...'......................-...... 39

Oriental sapphires.................................................. 46

North Carolina sapphires^......... ..........._............. ...... 46

Montana sapphires ........ ......................................... 47

Rock Creek sapphires.........-.-.....-..-..........-...---.... 50

Cottonwood Creek sapphires ...... _........................... 51

Yogo Gulch sapphires ............................. ............ 52

Etching figures............................... ..... .... 54

Corundum ..........-........ ...........;_.............,................ 55

North Carolina..... .... ........................... ................. 55

Macon County .........._. ...........,..-...........-......,.._, 55

Sheffield mine .......... .......... .1...................... 58

Clay County.. ................................................. 58

Buck Creek or Cullakeenee mine.......................... 58

Blue Ridge corundum tracts...................... ......... 59

Jackson County ................ ............................... 61

Georgia .......... .... ...... .-.....:......-......-.......-........... 63

Laurel Creek mine ........................................ 63

Track rock mine ......-......'.......... .................... 65

Foster mine .............. ..._.... .---.-..-............... 65

South Carolina...... ........ .... ........... .... .................. . 66

Pennsylvania........'...............-.-........... .......:.......... 66

Montana...___.,......._.... ....................................... 66

5
6 CONTENTS.

Distribution of corundum Continued. . Page.

Emery ........ ........-.....-....--- _.-.._____.___.-._.--..-----.--. 07

Massachusetts._-___.___........_._____._._..____.....-_._--_.-._.. 67

New York....... ...._........ ................................... 70

North Carolina............... ..................................... 72

Methods of mining corundum ...._. .,_._._..___._....__._..--.-.._.-_...-. 72

Methods of cleaning corundum ........................................... 74

Uses of corundum .......... J........................................ ...... 75

Vitrified wheel ..... .................................. ................... 77

Chemical wheel ...................................... ................ 77

Cement wheel ..................... .................................. 78

Other uses..-.-. ................. ....... .............................. 78

Corundum localities in the United States ....._.............-.......--..-. 79

Alabama ........-..-.....'-------..-..---....-.-.---. -..---.----...-..-. 79

California........-..-.--_..._._.-.._-....... ............... .^........... 79

Colorado.................................... .................... ..... 80

Connecticut................................................... ........ 80

Delaware..................... ........................................... 80

Georgia.......-..---..--.-........----...----.---...-..---...-.-..... 80

Maryland .................. r .......................................... .81

Massachusetts ........ ................--...-.....--...--.---.-.......'... 82

Montana .---... ...-.---....-...-...--.-..-.....---........--'. .......... 82

Nevada ...........-.--.--...--.... ..-----.............---..-..---.....' 82

New Jersey ................ ...._.......-.................-... ......... . 82

New York............................................................... 82

North Carolina......._._........-......-.-...... ......_....... ......... 83

Pennsylvania.. .........................'... ........................... 86

South Carolina ....... ......-............................"..... __..... 87

Utah.......:.....'.................. ..,...._...._._-_.---.......... 87

Virginia .............................^............................ 87

Alaska . ................................... .......................... . 88

Corundum localities in foreign countries ....'--.---...-.......-..-.-....... 88

Canada .;................. ....^.......................................... 88

India....---..--.-...................................................... 89

Turkey........... .. .......................__._..._....__....._..._.__ 91

Grecian Archipelago .................................................. 91

Other localities.............:....-.-....-......-...-..-..-.-...-.-..-.. 91
ILLUSTRATIONS.

Page.

PLATE I. Outcrop of peridotite at Buck Creek, Clay County, N. C......... 10

II. A, Bed of ruby-bearing gravel at Caler Fork, Cowee Valley, Macon County, N. C.; B, Ruby mine at Cowee Valley, N. C.. with 

plant for washing the gravels in the foreground............... 40

III. Ruby crystals from Cowee Valley, Macou County, N. C............ 42.

IV. Map showing location of sapphire deposits in Montana . ........ 46

V. Sapphire crystals, from Yogo Gulch, Fergus County, Mont ...... 52

VI.i Map showing location of the peridotite rocks and corundum localities of North Carolina and Georgia ........... ........... 54

VII. General view of the peridotite formation at Corundum Hill, Macon County, N. C... .. ...... ................................. 56

VIII. The <; Big vein " at Corundum Hill, between the peridotite and

gneiss, Macon County, N. C. ... ......................... ...... 56

IX. Upper end of big cut at Corundum Hill mine, Macon County,

N.C...... ................................................:. r ss

X. Open cut on a dunite vein at the Mincey mine, Macon County,

N.C......................... ................................ 58

XI. A, General view of the Buck Creek corundum mine and peridotite 

formation, Clay County, N. C.; B, Dunite vein of corundum in 

the peridotite formation at Buck Creek, Clay County, N. C.. . 60

XII. Open cut on peridotite-gneiss contact at Laurel Creek, Georgia,

with shaft house in foreground............................ ..... 64

XIII. A, Peridotite formation at Laurel Creek, Georgia; 7:?, Dunite vein

of corundum at Laurel Creek, Georgia..................... .. 66

XIV. .4, Corundum mill at Cullasagee, Macon County. N. C.; B, Interior view of corundum mill at Cullasagee, Macon County, N. C . 74 

Fig. 1. Ideal cross section of a corundum contact vein at the Corundum

Hill mine, Macon County, N. C -.....-.........................._ 18

2. Ideal cross section of a corundum-dunite vein at the Corundum

Hill mine, Macon County, N. C .................. . ... ........ .. 15

3. Ideal vertical cross section of a mass of peridotite soon after its intrusion in gneiss ..........;........................ ........... 16

4. Ideal vertical cross section showing a somewhat gradual transition

from corundum to peridotite...:..............'................... ' 17

5. Map of the Buck Creek peridotite area, showing the relation of the

amphibolite dikes........ ............. ..... ................... 22

6. Ideal vertical cross section of corundum in amphibolite at Hunters, 

Iredell County, N.C.......: ........... '. ......... .............

7. Corundum crystal showing concentric hexagons on basal plane ....

7
8 ILLUSTRATIONS.

Page. 

Fig. 8. Spokane Bar sapphire deposits, Lewis and Clarke County, Mont.... 48

9. Sapphire crystals from Missouri River bars, Montana ............. 50

10. Map of the peridotite formation at Corundum Hill, Macou .County,

N.C....................... .'..................................... 56

11. Map of the peridotite areas in the vicinity of Sapphire, Jackson 

County, N. C., showing the location of the different corundum 

mines ..................... ........... ....................... 62

12. Map of the peridotite formation at Laurel Creek, Georgia.... ..... 64

13. Map showing the location of the emery deposit at Chester, Mass... 68

14. Cross section of the Old mine at Chester, Mass., showing the amount

of emery taken out to April, 1899.....................,........... 69
OCCURRENCE AND DISTRIBUTION OF CORUNDUM IN 

THE UNITED STATES,

By JOSEPH HYDE PRATT.

INTRODUCTION.

In obtaining data for this paper many corundum localities were 

visited, especially those that were thought to carry the mineral in 

commercial quantity. Although all the occurrences of corundum can 

not be described in detail, they are all mentioned in the tabulated list 

of localities, page 70.

Considerable activity in corundum mining lias sprung up within 

the last few years, and several new occurrences of corundum in quantity have been brought to light, those of special note being in Ontario, 

Canada, where the corundum occurs in a syenite, and in Korth Carolina and Georgia, where it occurs in a gneiss or a quartz-schist.

The corundum localities in the United States are, with the exception of those in Montana, Colorado, and California, limited to the 

Appalachian region, the mineral having been found at various points 

throughout nearly its entire length. The mining of corundum has 

been, however, confined to a narrow section of the southern portion 

of that region, i. e., to northeastern Georgia and southwestern North 

Carolina, with the exception of the emery mines at Chester, Mass.

Often a distinction is made between emery and corundum, many 

persons not recognizing emery as a variety of corundum. There are 

three names in constant use to designate the varieties of corundum: 

(1) Sapphire, which includes all corundums, of whatever color, that 

are transparent to semitransparent; (2) corundum, including the 

translucent to opaque varieties of all colors; (3) emery, Avhich is a 

mechanical admixture of corundum and magnetite or hematite. The 

last two varieties are those used in the arts for abrasive purposes, 

emery being used in very much larger quantities than corundum. 

It is of course the presence of corundum in the emery that gives to 

it its abrasive qualities and makes it of commercial value, and the 

abrasive efficiency of emeries varies according to the percentage of 

corundum they contain.

Any corundum that is transparent is included under the head of 

sapphires, although many of these have distinct names in the gem 

trade. The blue sapphire is known as the oriental sapphire, the red

9
10 ' CORUNDUM TN THE UNITED STATES. [BUM,. 180.

sapphire as the oriental ruby, the green sapphire as the oriental 

emerald, the yellow sapphire as the oriental topaz, and the purple 

sapphire as the oriental ametliyst. There are also pink and white 

sapphires. The corundum gem or sapphire localities are usually distinct from the corundum localities, although very handsome gems 

have been found where the corundum was mined for abrasive purposes, notably at the Corundum Hill mine, Cullasagee, N. C.

Corundum as it is mined for abrasive purposes occurs as (1) sand, 

(2) crystal, or (3) gravel and block corundum. Sometimes all three 

types are found in the same deposit. The sand corundum consists of 

small grains or fragments of the mineral scattered through the vein. 

The crystal corundum consists of crystals up to 3 inches in length. 

Often these crystals have parting planes so thoroughly developed that, 

in crushing, the corundum breaks up into regular rhombohedrons, 

this breaking continuing to even the finer sizes and causing the grains 

of corundum to crumble when in use. This persistent regular breaking of the corundum destroys its cutting efficiency, for it is the irregular fracture that produces the best cutting edge. The block varietj^ 

often occurs in masses of almost pure corundum from 10 to 1,000 

pounds in weight. Again it occurs in large masses intimately associated with hornblende, feldspar, etc., making a rock which is tough 

and is difficult to work. Frequently the only way to break the masses 

is to bnild fires over them and then suddenly cool them by pouring 

water upon them. The parting planes are at times very noticeable in 

the block corundum, and are, as in the crystal corundum, detrimental 

to the commercial product. The parting planes are not lines of cleavage, but are planes developed in the mineral ~by synthetic twinning, 

usually parallel to the unit rhombohedron.

It is the hardness of corundum that makes it of so great value as 

an abrasive. Next to the diamond it is the hardest mineral known,

having a hardness of 9, while the diamond has a hardness of 10.

Garnet, which is sometimes used as an abrasive, lias a hardness of 

but 7 to 7.5. Corundum varies slightly in hardness; the sapphire 

varieties are generally considered the hardest, and of these the blue 

stands at the head. Some corundum has been observed that was 

readily scratched with a knife, as that from Acworth, Ga. The hardness of a corundum is often misjudged because, when made into a 

wheel, it does not cut so well as another, when in reality the degree 

of hardness may be the same in both cases, but the cutting efficiency 

;of one surpasses that of the other.

The theoretical composition of corundum is alumina (A12 03 ); but 

with one or two exceptions all corundums that have been examined 

vary from this by containing a small percentage of other constituents, 

principally silica (Si02 ), water (H2 0), and ferric oxide (Fe2 03 ). Nearly 

all corundums contain water, the amount varying from a trace to 2 

per cent or more. The amount of silica and ferric oxide varies also, 

some corundums containing neither of these constituents and some
BULLETIN NO. 180 PL. I

RIDOTITE AT BUCK CREEK, CLAY COUNTY, N. C,
PHATT.] MODES OF OCCURRENCE. 11

containing as much as 5 per cent of one ov the other. The purest 

forms of corundum that have been analyzed are the sapphire or gem 

varieties, which sometimes show over 99.5 per cent of alumina.

All corundums do not behave alike when heated to the high temperature necessary for the manufacture of vitrified wheels. While 

most corundums can, if properly cleaned, be used in the manufacture 

of these wheels, some will, when heated, crumble to a powder. It is, 

therefore, very essential, before beginning to mine a corundum deposit, 

to thoroughly test the ore and ascertain its adaptability to the manufacture of vitrified and other wheels.

MODES OF OCCURRENCE OF CORUNDUM.

Corundum was formerly regarded as occurring sparingly in-nature, 

and in only a few types of rocks, but it is now known to occur rather 

widely, and instead of being in quantity in the basic magnesian or 

peridotite rocks only, it has been found in abundance in syenites, 

in gneisses, and in schists. Although occurring in many of the crystalline rocks, it has been observed as a rock constituent in only a few 

of them. In some cases it is an original constituent of the rock, and 

in other cases it has been formed later, during the process of metamorphism.

In the United States corundum is known to occur in the following 

rocks: In peridotite (dunite arid saxonite), in biotite contact on saxonite, in enstatite, in serpentine, in chlorite-schist, in amphibolite, 

in norite, in basic minette, in andesite,, in syenite, in amphiboleschist, in gneiss, in mica-schist, in limestone, and in cyanite. These 

modes of occurrence are described below in the order in which they 

are mentioned,

CORUNDUM IN PERIDOTITES.

Extending from Tallapoosa County in east-central Alabama to 

Trenton, N. J., there is a narrow belt which contains disconnected 

outcrops of peridotite rocks; -north of New Jersey (in New York, 

Connecticut, Massachusetts, New Hampshire, and Maine) the outcrops are fewer and do not form a continuous belt. It is in the 

southern portion of this belt that these rocks have reached their 

greatest development, in some localities outcropping over an area of 

several hundred acres. In North Carolina and in the more southern 

portion of the belt the prevailing type of the rock is dunite, while in 

the northern portion the secondary rocks, serpentine and talc, are 

prominent. PI. I is a reproduction of a photograph of an outcrop of 

dunite at Buck Creek, Clay County, IsT. C.

Throughout nearly the entire southern portion of the belt the peridotite rocks show a freshness to almost the surface of the exposures, 

and there are few localities where there is any considerable area of 

peridotite entirely altered to serpentine. Under the microscope thin 

sections of the dunite show an alteration to serpentine between the
12 CORUNDUM'IN THE UNITED STATES. [BULL. 180.

particles of dunite. These peridotite rocks have been shown to be of 

igneous origin. 1 The blunt lenticular form in which they are found 

would be difficult to associate with any origin but that of an intruded 

igneous mass, which would also account for the apophyses that have 

been observed extending into the inclosing gneiss. At Webster, 

Jackson County, N. C., a large block of gneiss is completely inclosed 

by the peridotites in such a manner as could be attributed only to the 

intrusion of the latter while in a molten condition. The line of separation of the peridotites and the gneisses is always sharp, and there 

is no transitional zone' from the acid gneiss to the basic peridotite. 

Under the microscope the latter rock shows the granular structure 

characteristic of plutonic origin, the grains fitting perfectly into one 

another without cementing material.

Associated with all these peridotites is the mineral chromite, which 

occurs as disseminated particles near the borders of the lenticular 

masses of the peridotites. There is very little carbon found associated 

with these rocks, and what has been observed is unquestionably of 

secondary origin. -

Until recently the common occurrence of corundum (not including 

emery), and the occurrence in which the mineral had been found in 

commercial quantity, was in association with these basic magnesian 

rocks, peridotites, principally dunite. The country rock that is 

commonly in contact with.the peridotite is a hornblende-gneiss, but 

these peridotite formations have also been found in contact with a 

biotite-gneiss and with a mica-schist! Where the country rock is a 

gneiss it is usually considerably decomposed near the contact, and, 

while retaining the appearance of the unaltered rock, it readily crumbles to pieces Avhen handled. The peridotite is also more or less 

altered, the change being usually to serpentine.

The corundum is not an accessory mineral in these peridotites, but 

is either concentrated near the contact of the peridotite with the other 

country rocks or in pockets within the peridotite formation. A series 

of alteration products has been developed in this contact zone, so 

that the corundum is not found in direct contact with the peridotite, 

but is separated by intermediate zones of chlorite, enstatite, etc. 

Chlorite and vermiculite are usually developed between the corundum 

and the gneiss. For convenience, the occurrences of the corundum 

in these alteration products between the peridotite and the gneiss are 

designated contact veins, and those wholly within the peridotite 

dunite veins. 

In a cross section of a contact vein extending from the gneiss to the 

peridotite (dunite) the following sequence is often observed:

a. Gneiss, hornblendic or micaceous, apparently unaltered. 

b. Gneiss with same general appearance as a, but so decayed that the particles 

readily separate from one another.

l Elisha Mitchell Sci. Soc. Jour., Part It, 189.5, p. 35, and Am. Jour. Sci., 4th series, Vol. VI, 

1898, p. 50.
PR ATT.] MODES OF OCCURRENCE. 13

c. Yellowish vermiculites, varying considerably in thickness, the maximum 

being 6 to 8 inches; in places absent, 'so that fr comes directly in contact with d; 

where present, c often merges into d!.

d. Green chlorite, varying in thickness much like c, and in places absent.

e. Chlorite and corundum, sometimes with a little vermiculite. In places this 

mass maybe largely corundum, and it is what is called the "corundum vein," 

varying in thickness from a few inches to 12 or 15 feet.

/. Green chlorite; so far as observed always present, and varying in width from 

1 to 12 inches.

g. Enstatite; in places hard and compact, and in widths of several feet; usually 

merges into /i.

7i. Talcose rock, usually fibrous, varying in thickness from a few inches to several feet.

j. Dunite, more or less altered, friable, and stained with ferric oxide.

k. Dunite, apparently unaltered, quite extensive.

Between h aridj a seam of yellowish clay (i) is sometimes observed 

which often contains a narrow seam or fragments of chalcedony.

^^/vo''"/v-.^fcisr'.* '\r ;?*»';$

-__-r-.-j 7" -# /A '/ x- V /, '-" o

sr^c * ^,*>^ l<.^V/"°." t^^/*f,^\ii vn«L% t^. -.^-

»^^^7«r^ ^S"^«/U'7»*0^ n»\^>:r^^|i «H;-$:slis

^lvrV;'j5,''-»

FIG. 1. Ideal cross section of a corundum contact vein.at the Corundum Hill mine, North 

Carolina, a, fresh and unaltered gneiss; '6, decayed and unaltered gneiss; c, vermiculites; d, 

green chlorite; e, corundum-bearing zone; /, green chlorite; g, enstatite; /i, talcose rock; 

t, clay; j, altered dunite; fc, unaltered dunite.

From what could be learned by actual observation and inquiry 

among the miners, c and d are sometimes absent, and when this is the 

case, e, a mixture of chlorite, vermiculite, and corundum, is seemingly in direct contact, with 5. The chlorite, however, on the dunite 

side of the section is constant. The thickness of the several zones 

(a, 6, c, etc.) in such sections varies greatly at different places, and 

the distance across the sections may be said to vary at different 

points, even in the same region, from a few feet to 30 or 40 feet. The 

accompanying diagram (fig. 1) represents the cross section of a contact vein observed at the Corundum Hill mine, Cullasagee, Macon 

County, N. C. . '

In the diagram a represents gneiss, apparently fresh and unaltered, 

passing into &, which has somewhat the appearance of the unaltered 

gneiss, but is so decayed that the particles readily separate from
14 COKUNDUM IN THE UNITED STATES. IBULL. 180.

one another; o represents a narrow zone of vermiculites that is sometimes entirely lacking; d, a green chlorite (clinochlore) partially 

decomposed and forming the vermiculites of c; e, the corundumbearing zone, a mass of the green chlorite with crystals and fragments of corundum disseminated through it; /, another zone of the 

green chlorite; g, a mass of grayish, interlocking, crystalline sheaves 

of enstatite that merge into li; h, a fibrous talcose rock which passes 

into j; j, an altered dunite that is'some what friable find stained with 

ferric oxide; 7c, a hard and apparently unaltered dunite. Between h 

and j is a mass of soft, yellowish clay (i) containing fragments of 

chalcedony.

The line of contact between the zone of alteration products and the 

gneiss was very sharp and distinct in all the contact veins examined. 

The minerals developed between the corundum-bearing zone and the 

dunite are in great abundance and differ from those between that 

zone and the gneiss.

In a cross section of a dunite vein at a shaft near the southern part 

of Corundum Hill, in a distance of from 20 to 25 feet, the following 

has been observed:

1. Dunite, hard and apparently unaltered.

2. Dunite, somewhat friable and discolored, passing into 3.

3. Talcose rock, fibrous, merging into 4.

4. Enstatite, grayish and somewhat fibrous. 

 5. Green chlorite, 6 to 15 inches in width.

6. Green chlorite, corundum, and spinel, 6 to 8 feet wide.

7. Chlorite, same as 5.

8. Enstatite, same as 4.

9. Talcose rock, same as 3.

10. Dunite. same as 2.

11. Dnnite, same as 1.

The similarity of the two parts of the vein separated by the corundum zone, as already described and as illustrated in fig. 2, is very 

apparent.

In fig. 2, 1 and 11 represent the apparently unaltered dunite; 2 and 

10 represent dunite somewhat friable and stained and passing into 

3 and 9 a fibrous talcose rock, often carrying a green actinolite and 

some green chlorite; 4 and 8 represent a grayish, rather fibrous enstatite rock, which merges into 3 and 9; 5 and 7 represent a green chlorite, 

which passes into 6 a mass of chlorite, corundum, and spinel.

Although the section just described is a special case, it was observed 

that all of the dunite veins had the same character on both sides of 

the corundum-bearing zone. As has been already stated, either a 

talcose or a serpentine rock may be the limit of the cross section. 

In one of the dunite veins at Corundum Hill near the west end of the 

outcrop, the zone of corundum, chlorite, and vermiculites is in direct 

contact, both on the hanging and on the foot wall, with a serpentine 

rock. This zone is divided in one place almost pinched out by a 

mass of serpentine.
MODES OF OCCURRENCE. 15

At all of the corundum localities examined a careful search has been 

made to find the corundum directly surrounded by the peridotite, but 

it lias been thus observed at only one locality the Egypt mine, on the 

Avestern slope of the Sampson Mountains, in Yancey County, N. C. 

The few specimens obtained were collected by Mr. U. S. Hayes, who 

developed the corundum prope.rtj7' in that section. One specimen 

shows a prismatic crystal of the corundum surrounded by a granular 

peridotite (dunite), but with none of the ch.lo.ilte minerals which 

usually intervene. The dunite is not quite fresh, but is stained a 

yellowish brown by iron oxide and is rather friable. On the basal 

surfaces of the corundum a little muscovite is developed. This has 

been observed on corundum from other localities.

Spinel lias been found at a number of the corundum veins, and in

) » - ~

PIG. 2. Ideal cross section of a corunduin-dunite vein at the Corundum Hill mine, Macou 

County, N. C. 1, hard and unaltered dnnite; 2, friable and discolored dunite; 3, talcose rock; 

4, enstatite; 5, green chlorite; G, green chlorite, corundum, and spinel; '?, green chlorite; 8, 

enstatite; 9, talcose rock; 10, friable and discolored dunite; 11, dunite.

a few cases it is very intimately associated with the corundum. At 

the Carter mine, near Democrat, Buncombe County, N. C., the corundum is found, in masses of a white and pink color, intergrown with 

a greenish-black spinel. The masses of corundum and spinel are 

partially surrounded by a deep-green chlorite, which has also been 

developed in places between the corundum and the spinel, although 

this contact of the corundum and the spinel is usually very sharp and 

distinct. A massive, coarsely to finely granular spinel is found at the 

Corundum Hill mine, Macon County, N. C., which has disseminated through it small grains and fragments of pink and white 

corundum.

The mineral chromite, which has always been found associated with 

these peridotite rocks, occurs sparingly in many of the corundum 

veins. It is a well-observed fact 1 that where there is any quantity of

1 Am. Inst, Miu. Eng., Vol. XXIX, 18!W; February meeting.
16 CORUNDUM IN THE UNITED STATES. [BULL. ISO.

corundum found in the peridotite rocks there is a scarcity of chromite, and where there is a large quantity of chroniite there is a 

scarcity of corundum.

In a recent paper l I have discussed the origin of the corundum in 

the peridotite rocks, and have accepted the theory that the corundum 

was held in solution in the molten mass of the peridotite when it was 

intruded into the country rock, and that as the mass began to cool 

it was among the first minerals to separate. In these molten magmas 

the more basic minerals, corundum and spinel, would be the first to

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FIG. 3. Ideal vertical cross section of a mass of peridotite soon after its intrusion in gneiss. 

The corundum zone is greatly exaggerated.

separate, and this separation would take place along the outer border 

of the mass, for there it would first cool. Convection currents would 

then tend to bring into this outer zone a new supply of material carrying alumina, and when this zone was reached crystallization would 

take place and the alumina would be deposited as corundum.

Fig. 3 represents an ideal appearance of a vertical cross section 

of a mass of dunite holding corundum in solution, soon after its 

intrusion into a gneiss. In this figure the corundum zone has been 

greatly exaggerated, in order to illustrate better the cross section. 

The corundum would be concentrated toward the borders of the

1 Am. Jour. Sci., 4th series, Vol. VI, 1898, p. 49.
PKATT.] MODES OF OCCURRENCE. 17

dunite, and would make a sharp and nearly regular contact with the 

gneiss. The contact with, the dunite would be in some places sharp 

and regular and in other places very irregular, and 'masses of the 

corundum would penetrate the dunite. In some cases there would 

be a someAvh at gradual transition from the corundum to the peridotite, 

as represented in fig. 4. The rapid erosion to which rocks in a mounFiG. 4. Ideal vertical cross section showing a somewhat gradual transition from corundum to

peridotite.

tain region are subjected would readily wear them down to their 

present condition, represented by the dotted lines in fig. 3.

The corundum veins, I,«II, and III, in fig. 3, which at the present 

time have no connection with one another, but are each separate and 

distinct, were at the time of their formation part of the corundum concentrated along the border of the dunite. Some of these veins would

Bull. 180 01 2
18 CORUNDUM IN THE UNITED STATES. [BULL. 180.

soon be worked out, while others might be explored for a hundred or 

more feet without any apparent change in their width.

The most important observations leading to the adoption of this 

theory are: The occurrence of the corundum surrounded by granular 

dunite and also by serpentine; its occurrence with and. surrounded 

by spinel; the sharp contact between the gneiss and the alteration products of the contact vein; the development, on both sides of a 

corundum vein penetrating dunite, of the same sequence of alteration 

products, which are almost identical with those on the dunite side of 

a contact vein; the usual narrowing and pinching of the dunite veins, 

the trend of which is toward the center of the mass of peridotite, while 

the contact vein seems to extend down indefinitely.

At a number of the corundum veins in these peridotite rocks, feldspar, which is undoubtedly one of the original minerals of the rock 

and not a secondary product, is found associated with the corundum. 

There is a marked difference in the associated minerals when the feldspar is present; the chlorite is not so thoroughly developed, and 

enstatite is not so common, while margarite is rather abundant and 

zoisite is not uncommon. These last two minerals are rarely met with 

free from feldspar in the corundum veins.

The separation of alumina from these peridotite magmas has given 

rise to some interesting problems, which I have treated in a paper { 

published a short time ago. A summary of the conclusions reached 

is given here, as they bear directly upon the occurrence of the associated minerals, spinel, chromite, and feldspar, in a corundum vein.

From what has been observed in nature and from the experiments 

that have been made in the laboratory, it seems that the separation of 

alumina as corundum from molten magmas is dependent upon the composition of the chemical compounds that are the basis of the magma, 

upon the oxides that are dissolved with the alumina in the magma, and

upon the amount of alumina itself.

1. When, the magma is composed of a magnesium silicate without 

excess of magnesia, all the alumina held by such a-magma will separate as corundum.

2. Where there is an excess of magnesia in the magma just described, 

it will unite with a portion of the alumina to form spinel, and the rest 

of the alumina will separate as corundum.

3. Where there is chromic oxide present in a magma composed 

essentially of magnesium silicate (as the peridotite rocks), and only a 

very litlle alumina and magnesia are present, these, uniting, separate 

with chromic oxide to form the mineral chromite, and no corundum 

or spinel is formed.

4. When peridotite magmas contain, besides the alumina, oxides of 

the alkalies and alkali earths, as soda, potash, and lime, a portion of

>Ain. Jour. Sci., 4th series, Vol. VIII, 18U9, p. 337.
PRATT.] MODES OF OCCURRENCE. Itf

the alumina is used in uniting with these oxides and with silica to 

form feldspar.

5. There is a strong tendency for the alumina to unite with the 

alkali and the alkali-earth oxides to form double silicates like feldspars, whether such silicates form the chief minerals of the resulting 

rock or are present in relatively small amount. There is, however, 

little tendency for the alumina to unite with magnesia to form double 

silicates when the magma is a magnesium silicate.

CORUNDUM IN BIOTITE, CONTACT ON SAXONITE.

At the asbestos quarry near Pelham, Mass., there is a large lens of 

the igneous saxonite variety of the peridotite rocks penetrating the 

acid gneiss of the country. The saxonite is very much altered to a 

depth of 3 to 12 feet, when the hard nearly fresh rock is encountered, 

which is of a dull-black color and is made up :of grains of olivine and

the orthorhombic pyroxene, bronzite. The black color of the rock is 

due to disseminated particles of chromite and magnetite. Part of the 

magnetite may be due to the alteration of the grains of olivine, similar 

to that observed in the dunites of North Carolina, where, at the beginning of its alteration-, there is a deposition of magnetite in fine grains, 

which forms a network of black lines often outlining the grains of 

olivine.

Professor Ernerson has made a petrographical examination of this 

rock and describes it as follows: l

This is a very fresh mixture of olivine and enstatite, both dusted through with 

black ore, largely chromite. It is a dull-black rock of very great toughness. The 

olivine grains have often many crystalline faces. The enstatite is in rare, small 

plates, with parallel sides and irregular ends, and with a fine wavy lamination, 

which is often marked by lines of black ore, generally concentrated in sorue part 

of the plate, especially the center. Although nearly colorless or pale bronzy in 

common light, it has marked pleocbroism. It is plainly rhombic, and grades into 

the asbestiforin decomposition product in veins running through the section.

None of the anthophyllite that is so abundant in the decomposed 

portion of the saxonite were observed in the fresh rock.

From the fresh rock to the surface and the contact with the gneiss 

the saxonite is more or less completely altered, and penetrating through 

this there is a network of veins of anthophyllite, which are more or 

less asbestiforin. These veins vary in width from very thin seams to 

8 inches, with some that are very much wider, from which fibrous 

masses have been obtained 20 to 30 inches long. It is these veins of 

fibrous anthophyllite that constitute the asbestos quarry of Pelham.

The saxonite is separated from the gneiss by a band of bronzecolored biotite, usually 4 to 8 inches thi,ck, but in places reaching a 

thickness of 4 feet. In this wider portion there are nodules or imperfect crystals of corundum of a'grayish color mottled with blue.

1 Mon. U. S. Geol. Survey Vol. XXIX, p. 52.
20 CORUNDUM IN THE UNITED STATES. [BDLU 180.

These are often wrapped with chlorite. Nodules of a black-green 

hornblende and an emerald-green actinolite are also found in the 

biotite. There has been no great quantity of the corundum found.

This zone of biotite is probably the result of contact metamorphism 

of the saxonite on the gneiss, and the inclosing corundum was formed 

at the same time. This is similar to the large quantity of corundum 

occurring in biotite at the contact of saxonite and gneiss at the Bad 

Creek mine, Sapphire, 1ST. C. (See page 62.)

CORUNDUM IN ENSTATITE.

Enstatite is rather common as a secondary product at many places 

where the corundum occurs in peridotite, and is thus an associate of 

corundum at these localities. Occurrences are rare, however, of 

corundum in an enstatite that is the original rock. Where thus found 

the rock is made up chiefly of the orthorhombic pyroxene, enstatite, 

in bladed interlocking crystals of a grayish color. It is always more 

or less decomposed into talc.

At the Rattlesnake mine, Sapphire, Jackson County, N. C., and on 

the West Fork of the French Broad River, in Transylvania County, 

N. C., corundum has been found sparingly in the borders of an enstatite rock.

Enstatite rocks are somewhat common in North Carolina, but accessory minerals in them are rare, and the most common one observed is 

chromite, in small grains.

CORUNDUM IN SERPENTINE.

At a number of peridotite localities in North Carolina and Georgia 

crystals and fragments of corundum have been found that were surrounded by serpentine, but nowhere in this southern section of the

peridotite belt has corundum been found associated with the larger

masses of serpentine. In Chester and Delaware counties, Pa., 1 there 

is a long belt of serpentine rocks, part of which, at least, have been 

derived from, peridotite rocks, and in connection with these, in the 

eastern part of Chester County and the western part of Delaware 

County, corundum has been found. In this, as in the peridotite, the 

corundum occurs near the contact of the country rock. Considerable 

plagioclase feldspar is associated with the corundum in the vein in a 

manner somewhat similar to the occurrence of this mineral at the 

Cullakeenee mine, Buck,Creek, Clay County, N. C. In the South 

corundum has not been found as constantly associated with the serpentines as it is with the peridotites, but chromite is found very 

abundantly with many of them.

Cutting through the serpentines on the eastern slope of Spanish 

Peak, Plumas County, Cal., are white, coarse-grained dikes composed 

of corundum and ol

1 Geol. Survey Pennsylvania, C4 , 1883, p. 351.
PRATT.] MODES OF OCCURRENCE. 21 

CORUNDUM IN CHLORITE-SCHIST.

Besides being associated with chlorites in the peridotites just 

described, corundum is found in the long belts of chlorite-schist that 

traverse the country 10 or 12 miles southeast of Webster, Jackson 

County, 1ST. C. These chlorite rocks, which sometimes attain a width 

of several hundred feet, are traceable for miles across the country. 

Almost the only constituent of these rocks is a green scaly chlorite, 

though sometimes there are present small grains of feldspar, and 

occasionally needles of amphibole. The chlorite is in small scales, 

never very coarse, as is sometimes the case in the zones about the 

peridotite, and often these are so minute as to give the rock a very 

compact appearance.

In one of these belts, on Caney Fork of Tuckasegee River, Jackson 

County, N. C., corundum is disseminated through the chlorite in small 

rounded masses, ranging in thickness from an inch to minute grains,

and there the chlorite is not so compact as elsewhere. The corundum 

is usually wrapped with a white coating of mica, which is a secondary 

mineral derived from the corundum. The mica is often in radiating 

scales perpendicular to the outer surface of the corundum, and while 

in some cases it is very thin, in other cases it has replaced nearly all 

of the corundum, leaving but a grain of that mineral in the center.

CORUNDUM IN AMPHIBOLITE.

The occurrence of corundum in amphibolite is important, as the 

large deposits of emery corundum at Chester, Mass., are found in this 

rock. Under the head of amphibolite are included all those rocks 

that are composed entirely or chiefly of amphiboles. These rocks occur 

rather widely, including, as they do, those of Massachusetts, Georgia, 

and North Carolina, but with the exception of those that contain the 

emery they have not, up to the present time, been important in the 

production of corundum.

Associated with the peridotite rocks of Clay County, N. C., and 

the adjoining Towns County, Ga., are dikes of amphibolite, which are, 

for the most part, between the peridotite and the gneiss, although in 

some places they cut directly across the peridotite formation, but close 

to the contact of that rock with the gneiss. These dikes vary in width 

from 25 to over 300 feet, their average width being from 75 to 100 feet. 

The relation of these amphibolite dikes to the peridotite formation at 

Buck Creek, Clay County, 1ST. C., is shown in fig. 5.

The groundmass of this amphibolite is a grass-green amphibole, 

containing 17 per cent of alumina, nearly 12 per cent of lime, and 

one-half of 1 per cent of magnesia, which is best classified under the 

edenite variety of aluminous ainphiboles. The rich green color of the 

edenite is undoubtedly due to the presence of a small amount of chromic oxide, the analysis showing the presence of 0.38 per cent of this
22 CORUNDUM IN THE UNITED STATES. [BULL. 180.

oxide. Many microscopic grains of picotite or chromite are scattered 

through the groundmass of the edenite. There is also present, in 

widely varying proportions, the plagioclase feldspar anorthite. The 

feldspar is not constant in all of the amphibolites, and where it does 

occur it varies in size from minute particles to masses as large as a pea. 

The rock has often a very strikingly laminated structure, andjjrades 

from that to one which shows no lamination at all. It is exceedingly 

tough and very fine grained. The corundum, which occurs in the 

amphibolite as an accessory mineral, A^aries in size from minute particles to masses several inches in diameter, in which there are usually 

developed parting planes parallel to the unit rhombohedron. In color 

it varies from almost white to a deep ruby red, but the prevailing color 

is a deep pink.

,UD

FlG. 5. Map of the Buck Creek pevidotite area, showing the relation of the amphibolite dikes.

On account of the exceeding toughness of the rock, and more particularly on account of the low percentage of corundum, these amphibolites are not of commercial value as a source of corundum; they 

do, however, make handsome mineral specimens.

On the eastern slope of the Blue Ridge, in the vicinity of Statesville, Iredell County, N. C., corundum has been found associated 

with an amphibolite composed of a dark-green hornblende. On 

account of the thickness of the soil and the depth to which these 

rocks have been decomposed, there are few places where the fresh 

rocks are exposed, and little is known of their extent. At Hunters, 

7 miles west of Statesville, the amphibolite was exposed during

1 Bull. Geol. Survey North Carolina No. 11,1896, p. 59.
ITtATT.J MODES OF OCCURRENCE.

exploration for corundum, which, according to Lewis, 1 was found to 

occur in fine brown vermiculite, developed in /-ones along the borders 

of and penetrating the amphibolite, and varying in thickness from a 

few inches to 3 or 4 feet. Fig. 6 is an ideal illustration of the occurrence of corundum in the amphibolite at Hunters. In this figure, a 

represents a feldspar vein that is sometimes encountered in the midst 

of the vermiculites, 5; the feldspar is more or less altered to kaolin, 

and often bears corundum, although most of it was found in the 

vermiculite zones. I) represents the vermiculite zones carrying the 

corundum, which is in crystals and in rounded massesof crystals clustered together. Margarite sometimes accompanies it, and large masses 

made up almost entirely of these two minerals have been found on 

the surface in this region, c represents radiating borders of actinolitc 

that inclose large masses of what was once amphibolite, .but which

Vr, ' 7/ N ' ; - '/s>;

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F.10.0. ideal vertical cross section of corundum in amphibolite tit Hunters, Iredell County, N. C.

is now'nothing but a mass of ocherous clay, bearing occasional needles 

of hornblende and scales of vermiculite. The outer portions, d, are 

dark-green amphibolite.

CORUNDUM (EMERY) IN AMPHIBOLITE AT CHESTER, MASS.

The most widely known occurrence of corundum in amphibolite is 

that of the emery at Chester, Mass., an elaborate description of which 

is given by Prof. B. K. Emerson 1 in his exhaustive work on the geology of old Hampshire County, Mass.

Extending almost continuously across the State, north and south of 

Chester, there is a band of amphibolite that is conformable throughout its entire extent with the sericitic schists of this section of the

i Mon. U. S. Geol. Survey Vol. XXIX, 1898.
24 COKUNDUM IN THE UNITED STATES. [BUM, 180.

State. The strike of this band of amphibolite is dependent upon the 

windings of the schists, and its dip is approximately 90°. Its width 

will average only a few rods, but in the vicinity of Chester, a few 

miles both north and south of the town, it is three-quarters of a- mile 

wide, and it is in connection with this broad band that the emery is 

found. It occurs on the eastern side of the amphibolite and is sep^ 

arated from the sericitic schists by a narrow band of amphibolite, varying in width from an inch or two to nearly 18 feet. Sometimes there 

has been considerable serpentinization of the amphibolite, and the 

emery is separated from the schists by serpentine. Across the Westfield River from the point where the emery is first encountered, the 

amphibolite is replaced by serpentine, and it is in this bed of serpentine that crystals of this mineral, pseudomorphous after oliviue, are 

said to oecur, specimens of these being in the geological collection 

at Amherst College.

The amphibolite is in appearance a finely laminated rock made up 

of interrupted thin sheets of feldspar grains and of jet-black needles 

of hornblende, and usually contains more or less green epidote.

The sericitic schists on the west of the amphibolite, which are 

described by Professor Emerson under the head of the '' Rowe schist,"* 

are biotitic and feldspathic, and often contain garnets that are more 

or less altered to chlorite. The schists on the east are described as 

the "Savoy schist," 2 and are chloritic sericite-schists, mostly of a 

light-gray color, with a shade of green, due to the chlorite that is mixed 

with the muscovite. When the chlorite can not be seen with the eye 

it is readily detected under the microscope. In some places the proportion .of the chlorite has increased until there are considerable 

aggregations of this mineral along the planes of lamination. Garnet 

and pyrite are also abundant in certain portions of the schist.

The emery vein can be followed for a distance of nearly 5 miles, 

starting from the point where it is first encountered, at the north end 

of the broad band of amphibolite, on the left bank of the Westfield 

River, just above the railroad bridge of the Boston and Albany Railroad. The general strike of the vein is a little east of south and runs 

for the most part parallel to the line of contact of the amphibolite and 

schist. Emery is not found throughout the vein, but can be almost 

continuously followed by means of streaks of chlorite. The vein 

varies in width from a few feet to 10 or 12 feet, the average width of 

the emery being about 6 feet. Upon both sides of the emery there 

are usually developed thin seams of chlorite varying .from 1 inch to 6 

inches or more in width. During 'the early historj^ of the mine a seam 

of feldspar was encountered, about 12 inches wide, lying to the east 

of the emery and bordered on both sides by chlorite 3 or 4 inches Avide. 

There is also more or less chlorite developed in the mass of the ore 

body, which varies from some portions that are an almost pure magi Mon. U. S. Geol. Survey Vol. XXIX, 1898, p. 70. 2 Ibid., p. 15C.
PHATT.] MODES OF OCCURRENCE. 25

uetite to others where there is an intimate admixture of magnetite 

' and corundum. At the Sackett mine (described on page 68) the 

corundum, of a bronze color and luster, is coarsely crystallized, giving the ore a porphyritic appearance. Sometimes the corundum has 

crystallized out in blue and white crystals and in masses of a pound

or two in weight.

ORIGIN OF THE EMERY.

It is a perplexing question to decide from the examination of this 

and the surrounding rocks whether the amphibolite is of sedimentary 

or igneous origin, for there are many indications, that point to one and 

to the other. It is not improbable that some portions of this band 

of amphibolite, which extends across the State, may have been formed 

in one way and other portions in the other. Professor Emerson has 

examined this belt of rocks for practically its entire distance across 

the State, and while he is inclined to consider this band of amphibolite 

of sedimentary origin, he does not, if I understand him correctly, .see 

anything antagonistic to the view that at least a portion of this amphibolite is an intrusive igneous rock. I have examined only that portion of the amphibolite adjacent to the emery vein, and from my 

observations I had come to the conclusion that this part of the 

amphibolite band was an igneous rock that had been intruded into 

the schists along their line of weakness, and that the magnetite and 

emery had been the first minerals to separate out from this magma. 

The reasons that have led me to this conclusion are given briefly 

below.

The position of the amphibolite, with a dip of practically 90°, lying 

between the Rowe and Savoy schists, which would have been a line 

of least resistance, suggests an igneous origin. What seems to me 

opposed to the acceptance of a sedimentary origin for this broad 

band of amphibolite is the separation of the vein of emery and magnetite from the sericitic schist on the east by a band of the amphibolite 

varying in width from a few feet to 18 feet, which, as far as can be 

judged superficially, is identical in every way with the amphibolite on 

the west of the vein. Yet, if the amphibolite and emery are of igneous 

origin, it would naturally be expected that emery would occur on the 

west side of the amphibolite, but none has been found there, although 

it is not certain that it does not.occur.

Only a small amount of carbonates has been found in connection 

with the amphibolite and emery no more than could readily be 

accounted for as secondary minerals.

Then, again, chromite has been found in connection with the serpentine that is associated with the amphibolite, some of which is 

undoubtedly an alteration of this rock. The presence of the chromite 

in the serpentine is to me a very good indication of its igneous origin, 

and its being the alteration product of a basic magnesian rock. This,
26 CORUNDUM IN THE UNITED STATES. [uunr,. J80.

then, would indicate the existence of former masses of a basic magnesian rock which have been changed into serpentine, the serpentinization continuing into the ainphibolite for some distance.

The emery is not continuous along the strike of the vein, but occurs 

in a series of pockets in the vein that dip about 30° to the north. In 

going from one pocket to another along the strike there is often nothing to indicate the vein but a small seam of chlorite. The pockets are 

almost continuous in the direction of the so-called dip and hold this 

dip very constantly.

It seems to me that this portion of the amphibolite band was an 

igneous mass intruded after the formation of the sericitic schists, 

and either after or at the time these schists were tilted to their present position, and that the emery bed is the result of the differentiation of components of the mass that were held in solution by the 

igneous magma.

The theory that Professor Emerson1 proposes is also probable, viz:

That the emery-magnetite vein was originally a deposit of limonite which was 

formed by the replacement of limestone and into wh.ch alumina was carried by 

infiltrating solutions and deposited as allophane and gibbsite. The subsequent 

metamorphism of the bed, although it may well have been intimately connected 

with the extremely violent mechanical forces to which the strata have been subjected, was largely completed before these forces had ceased their activity, as is 

shown by the jointing and brecciation of the magnetite and emery. * * * 

The less altered ferruginous limestone below was changed into the epidotic 

amphibolite.

Many points that can be noticed support this conclusion, but these 

also indicate an igneous origin for the amphibolite. No fresh peridotite rocks have been observed in this section, and the nearest are 

probably across the Connecticut River at Pelham, where an igneous 

mass of saxonite is encountered. The presence, however, of chromite 

in the serpentine associated with this amphibolite is to me very good

evidence for believing that the serpentines have an igneous origin, 

and it is veiy probable that they are alterations of former masses of 

an intruded peridotite.

If any deep mining is undertaken on the emery, new evidence may 

be brought to light that will determine decidedly what may have been 

the origin of these amphibolites and emery deposits.

CORUNDUM IN NORITE.

In the vicinity of Peekskill, Westchester County, N. Y., corundum 

has been found associated with norites, which have been described 

by G. H. Williams. 2 These rocks belong to the Cortland series, of 

which the prevailing rock type, is one that is characterized by the 

presence of the mineral hypersthene. But though this mineral is

1 Mon. U. S. G-eol. Survey Vol. XXIX. p. 145.

"Am. Jour. Sci., 3d series, Vol. XXXIII, 1887, pp. 135,191.
VKATT.I MODES OK OCCURKElSrCE. . 27

there so abundant, a normal norite, containing1 nothing but a plagioclase feldspar and hypersthene, is extremely rare. Tliere is more 

or less biotite, hornblende, or angite developed in nearly all rocks of 

this class, so that there is a gradual transition from normal norite to 

mica-diorite, hornblende-diorite, and gabbro. The intermediate varieties are much more common than the extremes, and they have been 

classified by Williams according to the prevailing noiif eld spathic 

mineral. Where hypersthene prevails the rocks are grouped as 

norites, being subdivided into normal norite, horneblende-norite, inicanorite, and auglte-norite, according to the presence of these different 

minerals in the rock. These so grade into each other that no sharp 

line can be drawn between them.

Associated with the norites, 3 and 4 miles southeast of Peekskill, 

N. Y., are deposits of magnetite and emery. It is not at all unlikely 

that these veins are the products of the differentiation of the molten 

norite magma, by which the basic portion of the magma has been concentrated near its outer surface, a'gradual transition occurring toward 

the center to the more acid norite. This occurrence would be similar 

to that of the pyrrhotites Avhich have separated out from the norites 

of Norway, as described by Vogt. 1 In that case,the pyrrhotite was 

concentrated toward the border of the norite, and there is at some 

places a gradual transition from the pure pyrrhotite through a pyrrhotite-norite to the pure norite, while at others there is a sharp contact 

between them. The deposits of magnetite and emery are not in a continuous vein, but are more like segregated masses. Attempts have been 

made to work'these for both iron and emery, but as iron-ore deposits 

they were soon abandoned. They are still being worked to a certain 

extent for emery by the Jackson Mills Company, of Easton, Pa.; the 

Tanite Company, of Stroudsburg, Pa.; and H. M. Quinn, of Philadelphia, Pa. An examination of the emery ore by J. D. Dana 2 and G. H. 

Williams, 3 has shown that the corundum component is often scattered 

rather sparingly through the ore, and what had formerty been supposed to be green chlorite was found to be the iron-magnesian spinel, 

pleonaste. The corundum in the emery varies from -small, colorless 

grains to crystals 7 mm. in diameter, which show a hexagonal outline. 

In other parts of the emery the corundum grains are larger and of a 

bluish color.

The pleonaste, which is so commonly associated with the emery, 

has been found at the Cruger iron mine, in the eastern part of the 

township, as veins in a nearly normal norite, into which it passes by 

gradual transitions. The most compact specimens of the ore at this 

mine are found to contain the A^arious mineral components of the 

uorite, i. e., hypersthene feldspar, biotite, and garnet, no corundum 

having been observed here.

1 Zeitschr. fur Prakt. Gool., Nos. 1.4, and 7,1893. 

* Am. Jour. Sci., 3d series, Vol. XX, 1880, p. 199. 

3 Idem, Vol. XXXIII, 1887, p. 194.
28 COKUNDUM IN THE UNITED STATES. . [BUM,. 180.

This gradual transition of the pleonaste and iron ore into ihe normal norite and the occurrence of the norite minerals in the compact 

ore are strong evidence that these ore bodies were formed by the differentiation of the molten norite magma.

In the vicinity of these norites there are-small masses of peridotite, 

but no corundum has been found associated with them.

CORUNDUM IN BASIC MINETTE.

Near the entrance of Togo Gulch, in Fergus County, Mont., two 

parallel dikes of igneous rock have been observed cutting through 

the limestones. These dikes are about 800 feet apart, and can be 

followed for over a mile in a nearly east-west course. Their general width is from 6 to 20 feet, but they are occasionally 75 feet wide. 

They are much decomposed near the surface, but in working them 

for the sapphires which they contain the nearly unaltered rock lias 

been encountered..

The rock has a dark-gray, decided basic appearance, and is very 

tough, breaking with an uneven fracture. Scattered through it are 

light-green and white fragments, which are by far the most conspicuous of any of the mineral components of the rock. These are a 

pyroxene that is more or less decomposed and calcite. Some of these 

white fragments are probably the barium carbonate witherite, for in 

the concentrates obtained from washing the decomposed portions of 

the dike a considerable quantity of this mineral was found. Numberless crystals of pyrite, not over a millimeter in diameter and almost 

perfect trapezohedrons, were also found in these concentrates. A 

few scattered tablets of biotite, from 2 to 3 mm. in diameter, were 

observed.' The saiDphire variety of corundum is found rather sparingly in this rock in well-formed, flat, tabular crystals, some of which

are half an inch in diameter.

Professor Pirsson, of the Sheffield Scientific School, has made a petrographical examination of this rock, and describes it as follows: 1

In the section the rock at once shows its character as a dark, basic lamprophyre, 

consisting mainly of biotite and pyroxene. There is a little iron ore present, but 

its amount is small and much less than is usually seen in rocks of this class. The 

biotite is strongly pleochroic, varying between an almost colorless and a strong, 

clear, brown tint. It occurs in ragged masses, rarely showing crystal outline, and 

it contains a large amount of small apatite crystals. The pyroxene is of a palegreen tint, with the habit of diopside, and is filled witu many inclusions, now 

altered, but probably originally of glass; in some crystals these inclusions are so 

abundant as to render the mineral quite spongy. The grains sometimes show crys 

tal form, but are mostly anhedral and vary in size, though the evidence is not sufficient to show two distinct generations.

These two minerals lie closely crowded together, and no feldspars are seen in the 

rock. The interstices between them consist of a small amount of a clouded, brownish, kaolin-like aggregate, which appears to represent some former feldspathoid

1 Am. Jour. Sci., 4th series, Vol. IV, 1897, p. 421.
PRATT.] MODES OF OCCUKKENCE. 29

component, possibly leucite, perhaps aiialcite. * '"" '"' Some calcite in agglomerated grannies is also seen in the section.

This calcite does not appear to be.of secondary origin, and is probably due to fragments of limestone that were picked up as the igneous 

mass forced its way up through the limestones and were converted 

into calcite.

As has been indicated by Professor Pirsson ' in his paper, the amount 

of biotite in this rock shows that it is closely related to the minettes, 

and although it is lacking in feldspar it has the biotite and pyroxene 

of these rocks. It is a more basic type of these and is also similar to 

the shonkinites from the Highwood Mountains, Montana, described 

by Weed and Pirsson. 2

The sapphires, which are all of some shade of blue, occur but rarely 

in the rock, and from their sharp, distinct crystals and their general 

distribution it is very evident that.they have crystallized out of the

molten magma at the time of its intrusion, similarly to crystals 

of feldspar in porphyry. The alumina of the sapphires was not 

an original constituent of the magma, but, as lias been shown, by 

Pirsson, 3 was due to inclusions of clay sediments taken up from the 

strata through which it passed. The Belt formation, consisting of 

clay shales of great but unknown thickness, undoubtedly underlies the 

limestones, and the included fragments of these shales were the source 

of the alumina of the sapphires. These included fragments would be 

dissolved by the molten magma and thus form local areas that ANrould 

be very rich in alumina. As the magma began to cool corundum crystals would separate out in these alumina-rich areas.

CORUNDUM IN ANDESITE.

The occurrence of corundum in andesite in the United States was 

first described by Kunz. 4 He described a dike of andesite at Ruby 

Bar, near Eldorado Bar, on the Missouri River, 12 miles northeast of 

Helena, Mont. As described by him, this rock is in a dike cutting the 

slates of the country and is a vesicular mica-augite-andesite, which 

is made up of a groundmass of feldspar inicrolite and a brownish 

glass, in which are many particles of biotite and crystals of augite.

A similar occurrence has been observed by myself on the river 6 

miles above Eldorado Bar, at French Bar, which is nearly 12 miles 

due east of Helena. At this locality a narrow dike, 3 to 6 feet wide, 

was found cutting through the slates of this section. The trend of 

the dike is N". 5° to 10° E., and it dips about 45° E. It was encountered 

by miners who were working the gravels of the bar for sapphires, and it 

has been exposed at but one point, so that its extent is not known.

1 Am! Jour. Sci., 4th series. Vol. IV, 1897, p. 422.

2 Idem, Vol. 1,1895, p. 407.

3 Idem, Vol. IV, 1897, p. 423.

4 Idem, Vol. IV, 1897,p.418; Min.Mag.,Vol. IX, 1891,p.396; Seventeenth,Eighteenth,Nineteenth, 

Twentieth Ann. Repts. U. S. Geol. Survey.
30 CORUNDUM IN THE UNITED STATES. [BULL. 180.

The rock is fine grained, of a rather light-gray color, and a decided 

basic appearance. Biotite is the most conspicuous mineral and occurs 

in small, flat, tabular plates, sometimes with distinct crystal outline, 

and up to a millimeter or two in diameter. In some specimens of the 

rock there are nodules, 5"to 10 mm. in diameter, that appear to be 

partially decomposed feldspar. The augite, which is prominent in 

the thin .section, is not very apparent in the hand specimen.

Prof. L. V. Pirsson, of Yale University, has kindly examined thin 

sections of this rock for me and says-that the rock is an altered augitemica-syenite. It contains unaltered phenocrysts of a clear brown 

biotite which are well crystallized and which sometimes show slight 

resorption. It also contains phenocrysts of angite of a pale-brown 

color, variable in size, the largest 2 mm. across, replaced in the majority 

of cases by pseuclomorphs of calcite. Besides this pseudoinorphous 

calcite there is also a considerable amount of this mineral in irregular 

masses or streaks, which may in part be the filling of steam pores and 

in part be pseudoinorphous after hornblende; this, however, could not 

be definitely determined. The minerals just mentioned are embedded 

in a groundmass of a brown glass which is everywhere speckled and 

dotted with microlites of a lath-shaped plagioclase feldspar. These 

are small and somewhat altered, so that their determination is not 

entirely satisfactory, but they appear to be oligoclase.

The rock .is thus porphyritic, and the structure of the v groundmass is typical for the hyalopilitic structure of Rosenbusch. In many 

respects it closely resembles the augite-porphyrite of Weiselberg, 

weiselbergite. 1

One feature that is brought out in the thin sections is the somewhat laminated character of the rock in one direction, while in the 

slide, cut at right angles to this a well-characterized flow structure is 

observed, all the longer axes of the minerals pointing in one direction.

This indicates movements of flowing lava after the components had 

formed.

The corundum crystals occur very sparingly in the rock, and those 

that were observed were not so sharp and distinct as the blue sapphires.

I could obtain no definite information regarding the location of 

Ruby Bar and no one of the bars is now called by that name. It is 

possible that ,the bar described by Kunz is the same as the one now 

known as French Bar. From the description given of Ruby Bar, it 

is apparently not so far up the river as French Bar.

CORUNDUM IN SYENITE.

On a high foothill between Gallatin and Madison rivers, in Gal- 

.latin County, Mont., corundum has been found in a rock that is

Roseiilmsch, Mass. Gest., 3d eel., p. 953.
PRATT].. MODES OF OCCURRENCE., 31

 composed essentially of orthoclase feldspar, corundum, and biotite, 

with the feldspar predominating. This would classify the rock as a 

corundum-bearing biotite-sj^enite. The rock, for the most part, has 

a somewhat gneissoid structure, and in these portions the corundum 

is more or less finely divided, being in fine grains and small crystals. 

In other portions, where' the corundum is coarsely crystallized, the 

rock has something of a pegmatitic character, and the corundum is 

surrounded by the orthoclase. The crystals of corundum vary in size; 

the largest ones are 1£ inches long and from a quarter to a half an 

inch in diameter.. They are fairly well developed in the prismatic 

zone, but many of them, especially the larger ones, are rounded. In 

color they vary from bluish gray to almost colorless. The percentage 

of the corundum in the rock is large, and from a superficial examination it could be compared to the percentage of quartz in an average 

granite. The biotite is in small tablets, without definite crystal outline, and the tablets are often so arranged as to give the mass of the 

rock its gneissic appearance. The orthoclase did not show any crystal 

outline even in the larger fragments.

This occurrence of corundum was discovered by Prof. F. W. 

Traphagen, of Bozeinan, Mont., to whom I am indebted for the 

specimens.

From the appearance of the hand specimens, this occurrence of 

corundum is similar to that in the syenite of Ontario, Canada, recently 

described by Blue 1 and Miller. a

CORUNDUM IN AMPHIBOLE-SCHIST.

At the Sheffield mine, in Cowee Township, Macon County, N. C., 

corundum has been mined in a saprolitic rock at various times for a 

number, of years. In a shaft sunk to determine the depth of the 

corundum-bearing saprolite, solid, unaltered rock Avas encountered. 

The shaft1, which was 87 feet deep, passed through the following rocks: 

The first 12 feet (a) Avas through the saprolite, in which there were 

seams of kaolin; the next 2 feet (6) Avere corundum bearing. From 

14 to 28 feet (c) the same saprolite was encountered; the next 2 feet 

(d) were corundum bearing, followed by 10 feet (e, 30 to 40 feet) of 

the saprolite, and 2 more feet (/) that were corundum bearing. From 

42 to 63 feet (g) the rock began to be less decomposed, and from 63 to 

66 feet (h) another seam of; corundum-bearing rock Avas encountered. 

From this point to the bottom of the shaft the rock became more and 

more solid, until at 77 feet (i) the fresh rock Avas encountered. These 

various seams in the rock are very pronounced. They dip 30° toward 

the Avest near the top, but become nearly horizontal near the bottom

1 Traus. Am. Inst. Min. Eng., Vol. XXVIII, 1898, p. 505, and Ropt. Bureau of Mines, Ontario,Vol. 

VIII, Part II, 18!)!), p. 240.

2 Kept. Bureau of Mines, Ontario, A^ol. VII, Part III, 18!)8, p. £«, and Vol. VIII, Part II, 1899, 

p. 205. 
32 CORUNDUM IN THE UNITED STATES. [BULL. 180.

of the shaft. The seams of decomposed feldspar observed in a become 

less and less kaolinized, until in i the seams are of pure plagioclase 

feldspar. In i there are two seams of corundum similar to 5, d, and /, 

although in the fresh rock the corundum seams are not as pronounced 

as in the saprolitic rock. There is often a considerable amount of 

feldspar bordering the seams of the corundum. The general trend of 

the rock is about N. 5° to 10° E.

From, what could be seen of the solid and the saprolitic rocks, it is 

evident that the corundum occurs at intervals in the rock in seams a 

few feet in width. While the corundum may comprise 10 per cent 

or more of these veins, the amount in the rock that it would be necessary to mine would probably not be over a few per cent. The actual 

width of the dike is not known, but the saprolitic rock has been cut 

across for about 100 feet in a direction nearly at right angles to its 

strike.

The fresh rock at the bottom of the shaft is somewhat varied in 

appearance, and while it does not show any definite gneissoid structure, it sometimes closely'resembles it. There are streaks in the rock 

a few inches thick, the more finely divided portions of which are distinctly gneissoid.

Some portions of the rock are decidedly porphyritic, and contain 

phenocrysts of a light-gray amphibole, a centimeter in diameter, in a 

groundmass of feldspar. A large part of the rock is made up, however, of small, roughly outlined prismatic crystals of an amphibole, 

probably hornblende, and irregular fragments of plagioclase feldspar. 

The hornblende is almost black in color, but in thin splinters it has a 

bronze luster and a deep resinous color. Biotite of a deep-brown color 

occurs sparingly, and a pink garnet is rather abundant. This part of 

the rock has a gneissoid structure and contains the corundum. The 

corundum is of a light to a purplish-pink color and occurs in nodules

up to 2 or 3 cm. in diameter. Some streaks in the rock are. highly 

garnetiferous, composed essentially of the garnet and plagioclase 

feldspar or of garnet and biotite. Chalcopyrite occurs very sparingly in these portions of the rock. Small particles of graphite have 

been observed in the coarsely crystallized portions.

Professor Pirsson has kindly made a microscopical examination of 

this rock, the results of which are embodied in the following paragraphs:

In thin section the microscope disclosed the minerals hornblende, plagioclase 

feldspar, garnet, biotite, muscovite, staurolite, and rutile. Hornblende is the most 

common, forming about two-fifths of the section, while of the remainder plagioclase and garnet occur-in about equal quantities and the others in comparatively 

insignificant amounts.

The hornblende is formless, but tends to irregular columns, almost invariably 

extended in the plane of schistosity. It has very rarely a somewhat stringy tendency in its cleavage, but is usually homogeneous in broad plates. Its color is a 

clear olive brown, and it is somewhat pleochroic, but not strongly so. It is every-
PHATT.J ' MODES OF OCCUEEENCE. - 33

where dotted by the small grains of garnet, which rarely show good crystal form. 

The garnet occurs associated also with the plagioclase.

The plagioclase occurs twinned according to the albite law only. In sections 

perpendicular to 010 the lamellae show extinction as great as 30°, and the plagioclase is therefore rich in lime and as basic as Jabradorite, which it probably is. 

It shows strong evidence of shearing movement in the rock; it is often broken, 

exhibits rolling extinction, and the albite lamellae are curved and bent. It runs 

along the planes of schistosity between the feldspars and forms a mosaic of 

angular broken grains.

Staurolite was found in rather broad, irregular grains, and rutile in small, 

irregular grains and well-crystallized prisms.

Professor Pirsson lias indicated that the character and structure of 

this rock, composed chiefly of amphibole, labradorite, and garnet, 

suggest most strongly that it is a metamorphosed igneous rock of the 

gabbroid family. During metamorphism the augite of the gabbro 

would be converted into the brown hornblende; any iron ore that was 

present would be taken up by the hornblende and garnet. The 

rntile would have resulted from the titanic acid that is a regular component of the iron ores in these gabbro or diabase rocks. Staurolite 

is a mineral that would be rather naturally expected, as it is usually 

a mineral of metamorphism, and its natural home is in the schistose 

rocks. The feldspar has suffered the least (except the corundum) 

chemically, and shows only the shearing of dynamic processes.

The corundum does not occur in crystals, bu'o in small fragments 

and in elongated nodules, which are cracked and seamed and appear 

to have been drawn out by the shearing processes. The general 

character and shape of the fragments of corundum would indicate 

that they were original constituents of the igneous rock and were not 

formed during its metamorphism..

The exact classification of this rock is not easy, but it is probably 

an ainphibole-schist.

CORUNDUM IN GNEISS.

Corundum has been found in North Carolina in the ordinary gneiss 

of the same belt of crystalline rocks in which the peridotites occur. 

A number of occurrences, part of which may be corundum in gneiss, 

are described under the head of mica-schist; some of the rock that 

was at first thought to be a gneiss is now known to be a quartz-schist.

In the eastern part of Clay County, N". C., on the southern slope of 

Gross Ridge of the Chunky Gal Mountains, just above Thumping 

Creek, corundum has been found in the gneiss at a number of points. 

The rocks are 'so covered with soil and decomposed rock that the 

exact relation of the corundum-bearing gneiss to the normal gneiss 

can not be determined, but from what can be seen the former appears 

to be in narrow bands cutting through the latter. In structure the 

gneiss is distinctly laminated and very fine grained, except the portions immediately surrounding the corundum, where its constituents

Bull. 180 01 3
34 CORUNDUM IN THE UNITED STATES. [BULL. WO.

are much more coarsely crystallized, especially the biotite. It is a 

hornblende-gneiss, showing but little mica except where associated 

with the corundum.

The corundum occurs in nodules and crystals, half an inch and 

smaller in diameter, sometimes wrapped with muscovite in a manner 

similar to that described for the corundum in the chlorite-schists 

(p. 21). The crystals are prismatic, with the length of the prism 

usually two or three times its diameter. Occasionally they are very 

flat, with the prism not over a quarter of an inch in length and half 

an inch in diameter, and from their appearance these crystals are 

known locally as "button" corundum.

This occurrence of corundum in gneiss is in no way associated with 

the peridotite rocks of this section of the country. It is, however, 

very similar to the occurrence of corundum in quartz-schist described 

below. None of the peridotite rocks in which the corundum is so 

commonly found in this section of North Carolina have been found 

associated with these bands of gneiss.

CORUNDUM IN MICA-SCHIST.

It has recently been observed that portions or bands of the crystalline rocks of the southwestern part of North Carolina and the northeastern part of Georgia are corundum bearing. The composition of 

these rocks varies from those that are a normal gn'eiss to those that 

contain no feldspar and can best be described as quartz-schist composed of biotite, mica, and quartz. Some portions of the rock are 

rich in garnet, others are almost entirely free from this mineral, and 

occasionally there are also small bands of white quartzite. The rocks 

are distinctly laminated and are frequently intersected by granitic 

dikes, some of which are coarsely crystallized and of a pegmatitic 

character. These dikes are often parallel with the bedding of the

schists, although many of them cut irregularly through them. Where 

these dikes are parallel to the bedding of the schists, the laminated 

structure of the latter is much more apparent. The general strike of 

these crystalline rocks is about northeast to southwest and the dip is 

about 30° NW. . Portions or bands of these schists are corundum bearing, but they 

are irregularly denned and gradually merge into the normal rock. 

They have a similar relation to the normal schists as the garnet-bearing 

bands of a gneiss to the normal gneiss in which they occur. These 

bands are not veins in any sense of the word, but are simply portions of the same mass of crystalline rocks in which corundum occurs 

as a constituent of the rock. They vary in width 'from a foot or 

two to 12 or 15 feet, but in these wider ones the corundum-bearing 

portion is not continuous and is intercepted by streaks of barren rock 

and granitic dikes. The bands can be traced for a distance of 5 or 

6 miles in a northeast-southwest direction, sometimes outcropping
PKATT.] MODES OF OCCUBREIN'CE. 35

continuously for nearly a mile. There are at least two of these corundum-bearing bands which are parallel to each other and. about 2 miles, 

apart. The only variation that has been observed in them is in the 

percentage of corundum and garnet; otherwise they are identical. 

The amount of corundum is never large, and from determinations 

made on samples from various parts of the deposits it will not average 

over 4 or 5 per cent.

The corundum occurs for the most part in small particles and fragments that have no regular shape and are of a gray, white, and 

bluish-white color or almost colorless. It is also in crystals which 

vary in size from some that are very minute to some that are 2^- inches 

long and about one-half inch in diameter, and which are usually fairly 

well developed in the prism zone.

It is probable that these schists are the result of the rnetamorplrism 

of sandstones and shales formed from alluvial deposits many thousand feet in thickness that were once the; bed of the ocean. By lateral compression these have been folded and raised into the mountain 

ranges of this region. That these have been much higher than at 

the present time is very evident from the granitic dikes, which are of 

deep-seated origin. By decomposition and erosion the mountains 

have been worn down to their present condition, thus exposing the 

schists in contact with the granitic dikes which have aided in their 

thorough metamorphism. The shales were rich in alumina, and during their metamorphism the excess of the alumina crystallized as 

corundum along the planes of lamination, so that during the subsequent weathering the corundum has been left in knotty nodules, studding the surface of the rock and giving it the appearance of containing 

a high percentage of the mineral.

Gentli' has described an occurrence of corundum in Patrick County, 

Va., about 2 miles from Stuart, where it has been found in the micaschists on a knob of Bull Mountain. These schists are talcose and 

chloritic in character and are intersected by a number of granitic 

dikes. The'portions of the schists in which the corundum occurs are 

gneissoid in character. This occurrence is decidedly different from 

that in Clay County, N. C., and more like the corundum-bearing 

schists near the headwaters of Caney Fork of Tuckasegee River, in 

Jackson County. The schists are in rather narrow bands that can 

be followed for some distance across the county. They are not true 

chlorite-schists like those described on page 21, but are made up 

largely of an elastic mica (probably muscovite) with some chlorite. 

The corundum occurs in rough crystals and nodules up to 1 inch in 

length and half an inch in diameter, of a grayish-white to white color 

and colorless. It is readily cleaned, and tests made upon the cleaned 

product show that it is well adapted for the manufacture of the vitrified wheel.

' Am. Jour. Sci., 3d series, Vol. XXXIX, 1890, p. 47.
36 COBUNDUM IN THE UNITED STATES. [BULL. 180. 

CORUNDUM IN LIMESTONE. 1

Extending from By ram, Sussex County, N.- J., to Warwick Township, Hew York, a distance of about 25 miles, there is a belt of limestone having a general northeast-southwest strike, which, widens 

out toward its northern end. About 1828 a specimen of sapphire 

corundum was found at Franklin Furnace in a detached piece of 

rock composed essentially of feldspar, and although-search was made 

no more specimens were found in this vicinity. A few years later 

sapphire corundum was found in Newton Township, about 6 miles 

from Franklin Furnace, embedded in a feldspar and partly surrounded 

by a carbonate. This occurs near the contact of the limestone with 

the granitic rocks of this section, and it is very evidently the result 

of contact metamorphism. Dana reports the occurrence of sapphire 

corundum in these limestones near Newton and Vernon, Sussex 

County, N. J., and near Amity, Orange County, and Crugers Station, 

Westchester County, N. Y. . Prof. W. P. Blake 2 has described the occurrence of red sapphire 

corundum in the white crystalline limestones in Vernon Township, 

Sussex County, N. J. The finest specimens were ruby red in color 

and the others were of various shades of purple. The crystals were 

translucent, but no transparent ones were observed. They were 

embedded in the limestone and it is not improbable that crystals 

may occur in the similar rocks of the adjoining counties of New York.

The New Jersey occurrences seem to be well authenticated, but 

those from New York are not. In the report of the New York State 

Museum for 1895 011 the mineral resources of the State there is no 

mention of the occurrence of corundum at this locality, and in the 

report for 1898 it is stated that no sapphire corundum is found in the 

State.

CORUNDUM IN .CYANITE.,

The occurrences of corundum associated with cyanite are quite 

widespread, and at times there are large masses of cyanite in which 

are numerous hexagonal crystals of corundum. At Litchfield, Conn. , 8 

a mass of cyanite containing crystals of a dark, grayish-blue corundum, 

which was said to have weighed 1,500 pounds, was found. Large 

masses of cyanite have been found at various points in North Carolina in which there were well-developed crystals of corundum.

All the occurrences that have been noted have been from surface 

specimens, and the rocks in the vicinity have always been either schists 

or gneisses. It is without doubt in connection with these rocks that 

the cyanite and corundum originated. I do not believe that the cyanite is usually an alteration product of the corundum, as has been sug1 Am. Jour! Sci., 1st series, Vol. XXI, 1832, p. 319.

2 Idem, 2d series, Vol. XIII, .1852, p. 116.

3 Idem, 1st series, Vol. VI, 1823, p. 210.
PRATT.] DISTRIBUTION. 37

gestecl by Genth, 1 but that they were both formed during the metainorphism of the rocks from which the schists and gneisses have been 

derived.

SUMMARY OF CORUNDUM OCCURRENCES.

From the facts presented in the preceding pages, the occurrences 

of corundum are seen to be of much greater variety than was 

formerly supposed. While the large concentrated masses are still 

confined to the basic magnesian rocks, corundum is scattered in small 

amounts through a number of other rocks, and in the aggregate is in 

very large quantity.

Of the igneous magmas there are two that are very distinct from each 

other and that can be designated as the lime-magnesia and the alkaline series. In the first the mineral components of the rock are free 

from alumina, and where there has been alumina in solution in the

molten magma it has all separated out either as corundum or spinel.

In the second series, however, it is only the excess of alumina that 

has separated out as corundum, by far the larger percentage having 

united with the alkaline oxides to form a feldspar. In all the occurrences that have been examined this phenomenon has been constant. 

It is very evident that there are magmas that contain an excess of 

alumina just as there are magmas with an excesss of silica, and it is 

evident that the alumina separates out as corundum in the saine'manner that silica separates as quartz in granitic rocks.

DISTRIBUTION OF CORUNDUM.

Most of the corundum that lias been mined for abrasive purposes 

has been obtained from the eastern part of the United States, and has 

been found associated with the long belt of basic magnesian rocks 

extending from Massachusetts to Alabama. It is in the southern portion of this belt, in North Carolina and Georgia, that these rocks have 

their greatest extent, and it is in this region that the greatest quantity 

of corundum has been found. During the past few years, however, 

North Carolina is the only State that lias produced any corundum and 

Massachusetts and New York the only ones that have produced any 

emery.

While the production of corundum has been limited almost entirely 

to one locality in North Carolina, it is not because this is the only 

known deposit of this mineral in quantity, but because the better 

deposits have not been worked. The emery deposit that has proved 

of the most economic importance, and which has produced practically 

all the emery mined in the United States, is at Chester, Mass. The 

amount of corundum that has been mined during the past year is 

very much less than the amount of emery, although its market value

' Ain. Philos. Soc., Vol. XIII, 1873, p. "i&.
38 COKUNDUM IN THE UNITED STATES. [BULL. 180.

is twice that of the emery and there is a large demand for a wellcleaned commercial product. There are a number of reasons for this 

condition: the better deposits have been so controlled and tied up 

that they could not be worked, an imperfectly cleaned product has 

been put on the market, and other minerals have been substituted for 

this one.

It is still too soon to predict to what extent recent discoveries 

of corundum in Canada and India will add to its production. Some 

of the Canadian deposits in Ontario were granted by the government 

to the Canada Corundum Company, Limited, of Toronto, and this 

company began extensive operations on the deposits at the beginning 

of 1900. This corundum, which occurs in a syenite similar to that 

described on page 30, has been thoroughly tested and has given fairly 

satisfactory results. The reports of the bureau of mines at Toronto 

show that this ore carries 14.7 per cent of corundum and that a very 

clean product is obtained. If the ore from this extensive Canadian 

bed continues to carry so large a percentage of the mineral, can be 

readily cleaned, and shows good abrasive qualities, this deposit should 

play an important part in the world's production of corundum (see 

page 88).

The India corundum occurs at Pipra, South Rewah. It is pink in 

color, with a fine-grained massive structure, and very tough. It is 

reported that there is an unlimited supply of this material, and it 

has already been used in this country in the manufacture of certain 

oilstones (see page 89).

In the following descriptions of localities those that contain sapphires are first taken up, then the corundum, and last the emery.

SAPPHIRE OR CORUNDUM GEMS.

The properties of a mineral that determine its rank as a gem are

hardness, color, rarity, index of refraction, and luster. As an illustration of the extent to which the hardness affects the value of a mineral for gem purposes, sphalerite might be cited. This mineral, which 

has an index of refraction and a luster not far below that of the diamond, has a hardness of only 3.5 to 4, which effectually cuts it off 

from being a gem mineral.

Corundum has properties that place some of its varieties among 

the most valuable gems. With the exception of the diamond, it is the 

hardest mineral known, .and the rarity and color of the ruby, the red 

corundum, has made that gem, when more than a carat in weight, 

more valuable than a diamond of corresponding weight. Corundum 

has been found in almost all the colors of the rainbow, and in the 

following list its gems have been classified according to color. They 

are very often designated by the prefix "oriental," to distinguish them 

from gems of the same name whose mineral composition and character 

are entirely different.
PBATT.] CORUNDUM GEMS. 39

Sapphire or corundum gems.

Oriental or true ruby.._.---______.__--.Red of various shades.

Oriental sapphire...__._.-..__._._...__--_Blue of various shades. 

Pink sapphire ---.......---..--...-..... Rose or pink.

White sapphire.._.-....--.... .....

Diamond spar .......................... [ Colorle88-

Opaline.................. ........._ ... \ 

Girasol........ -...-----.---.----.... > Pale blue or bluish white.

Hyaline ... ............... ..-.......-..- )

Oriental amethyst ..........._.--.--....Purple.

Oriental emerald ....... ...............Green.

Oriental topaz_.........-_-..-....-..-..Yellow.

Star sapphire ..........--._...'........ )

Chatoyant ...------..----..-..--..--. . [ Opalescent.

Asteria............... .................)

The gems occur in the mines in three forms: First, as crystals, of

which there are two distinct forms, (1) hexagonal prisms terminated 

by rhonibohedrons and pyramids, sometimes with basal plane, the 

larger crystals being often rounded or barrel-shaped,' and (2) flat, 

tabular crystals, where the basal plane is very largely developed; 

second, as transparent Qolored portions of larger massive pieces of 

corundum; third, as nodules of finer and clearer material in a mass 

of cleavable corundum, often having the appearance of rolled pebbles 

when separated from, the mass of corundum.

ORIENTAL RUBY.

The most important of the sapphire gems is the oriental .ruby, which 

varies from rose, pinkish, dark-red, and purplish, to pigeon-blood 

color, the most highly prized. The rubies are very likely to be flawed, 

and when examined many of the cut stones are found to contain .flaws 

of one character or another. The stones are often so cut that these 

flaws are distinguishable only by the aid of a magnifying glass.

The finest rubies of pigeon-blood color are those found in the Mogok 

district, about 90 miles north-northeast of Mandalay, in upper Burma. 

Small but fine rubies, often, however, of a pink color or a purplish tint, 

are found at .Ratnapoora, in Ceylon, and of a dark-red color, similar to 

that of a garnet, in Si am. The rubies of the Burma district are found 

in. situ in. limestones, but the mining is confined almost entirely to the 

gravels.

At the Corundum Hill mine, Cullasagee, N. C. (see description, 

page 55), various shades of gem ruby corundum have been found. 

Two of the best rubies of good color that have ever been found at 

this mine are in the collection of Clarence S. Bement, of Philadelphia; there are also a number of line ones in the United States 

National Museum at Washington. Many of the smaller crystals of 

various shades of pink to red are transparent near the outer surface 

and near their extremities, and from these small gems can be> cut, but
40 CORUNDUM IN THE UNITED STATES. [BULL. 180.

few that are worth $100 have been obtained from them. These smaller 

crystals are usually well developed and have a clean-cut form. The 

faces commonly developed on these are the base, c, 0001; the unit 

prism, m, 1010; the unit rhombohedrou, r, 1011, arid the pyramid, n, 

2243, more rarely observed.

The North Carolina locality for corundum gems which at the present time is attracting the most attention is the tract of laud between 

the Caler Fork of Co wee Creek and Mason Branch, tributaries of the 

Little Tennessee River. 1 This tract is situated in Macon County, 

almost 6 miles below (north of) the town of Franklin. The nearest 

railroad station is Dillsboro, Jackson County, on the Southern Railway, about 12 miles to the east. The bottom of the valleys are about 

2,500 feet above sea level, and the mountain peaks or knobs in the 

immediate vicinity rise to a height of 3,000 or 3,500 feet.

In the gravels of Caler Fork Valley pieces of crystals of red corundum were picked up by the people of the district, Avhich led to the 

driving of two or three tunnels with the expectation of striking the 

vein and finding the corundum in sufficient quantity for commercial 

purposes. Work in this direction was soon abandoned, and for a 

number of years there were only prospecting and a little mining for 

the red corundum for gem purposes.

Systematic search was made, which revealed the fact that ruby 

corundum was to be found in the gravels of Caler Fork Valley for a 

distance of 3 miles. In 1895 the American Prospecting and Mining 

Company, of New York, bought out the old claims and began work on 

a systematic-basis. The property owned by the company is a large 

tract on both sides of Caler Fork of Cowee Creek and nearly all the 

land in the northern part of the watershed of Mason Branch, a total 

area of about. 5,000 acres.'

The gravels in which most of the rubies have been found are covered by soil averaging about 2 feet in depth, but varying from 1 to 5, 

and they are about 3 feet higher than the present "alluvial gravel of 

the stream. PI. II, A, is a view of one of the gravel beds that is 

being worked for rubies, just west of the company's office. The 

gravel in this part of the valley, which is overlain with 3 to 5 feet of 

soil, is composed of waterworn masses of quartz and small pebbles of 

gneiss and quartz, and is much cleaner in appearance than the gravels 

a mile farther up the creek, at In Situ Hill, where most of the miningwas carried on during 1898. Fifty feet above the level of this gravel 

another bed was discovered . at In Situ Hill which carried ruby 

corundum.

In washing these gravels for ; the rubies, hydraulic processes have 

been used very similar to those used in the West in washing goldbearing gravels. All the soil, as well as the gravel, is washed into a 

short line of sluice boxes (a of PL II, B) which lead into a large sieve

N »Am. Jour. Sci., 4th series, Vol. VIII, 1899, p. 370.
U. S. GEOLOGICAL SURVEY

1ULLETIN NO. 180 PL. (I

A. BED OF RUBY-BEA RI MG GRAVEL AT CALER FORK, COWEE

COUNTY, N. C.

VALLEY, MACON

RUBY MINE AT COWEE VALLEY, N. C, 

Plant for washing the gravels is shown ,n the foreground; a, s!u,cebox ; h, s,eve boxes; c, rocker.
P'RATT.] - COKUNDUM GEMS. 41

box (6 of PL II, .£>), where the large pieces of rock and bowlders are 

removed and most of the dirt and fine gravel is washed out. They 

are then shoveled into a rocker (c of PL II, J5), where they are further 

cleaned and concentrated, the final concentration of the rubies being 

done bj7 hand.

No basic magnesian rocks or serpentine derived from them, in which 

most of the corundum of North Carolina occurs, have been found in 

this valley. Corundum Hill and the Ellijay corundum region are, 

however, less than 10 miles to the south.,

" Although, in many respects, the occurrence of the rubies and their 

associate minerals in the Cowee Valley is similar to the occurrence of 

the ruby in Burma, no limestone has been found near the alluvial 

deposits, the nearest point at which limestone has been found being 

at Cullowee Gap, about 8 miles to the southeast.

The country rock of the district is a gneiss, of a gray, fine-grained 

variety, which has a great many small garnets disseminated through 

it. The rock for the most part is in a highly decomposed condition, 

but there are small exposures of the undecomposed rock in many 

places. The gravels in which the rubies are found rest on a soft rock 

known as saprolite, which is the result of weathering of the basic 

silicate rocks in place. By means of shafts and the workings at the 

gravel washings it has been shown that at a depth of 35 feet or more 

these saprolitic rocks contain fragments of the undecomposed rock 

and pass into such rocks as eclogite-amph ibolite and a hornblendic 

gneiss.

A narrow dike of hornblendic eclogite a few feet in width is 

exposed near the present Avorkings of the company and can be traced 

lor about 100 yards.

No rubies have been found in the undecomposed rock, but at In 

Situ Hill small rubies of a. rather pale color were found .in a narrow 

band of saprolitic rock. This band was, however, cut off by slickenslides so that it could not be followed in any direction. There 

are four parallel slickenslides that have been exposed at one place in 

 i e workings, the general direction of the slides being N. 75° E. Some 

of these are 70 feet in length and of unknown depth. It is very evident that there lias been a great deal of disturbance in this immediate 

vicinity through the breaking of the rock masses by faulting, the 

i'f T,dy influx of water having caused the reduction of the rocks to 

their saprolitic condition.

In washing the gravels and masses of saprolite, masses of uiideGI nposed rock have been uncovered, and. in the center of these

/diiles of the pure hornblende rock have been found. The saprolite 

 clering these nodules often contains particles and crystals of 

mdiim.

uess than 2 miles to the east of In Situ Hill, beyond Betts Gap of 

Cowee Mountains, corundum of a gray to bluish color, but highly
42 CORUNDUM IN THE UNITED STATES. [HULL. 180.

crystallized, has been found in hornblende-gneiss. One mile a little 

north of west, at the Sheffield mine, pink corundum has been found 

in amphibole-schist (see pages 31 and 58).

An association of corundum peculiar to this locality is with the 

garnet, rhodolite. Corundum and garnet occur not only constantly 

together in the^saprolitic material and in the gravels, but corundum 

crystals have been found that bear the impression of the garnet. By 

means of wax a mold was taken, of these impressions, and they were 

shown to be either the dodecahedron or trapezohedron. Then again 

some of the ruby crystals when broken are seen to have a garnet 

inclosed, and the garnet can often be seen in the transparent ruby 

crystal and the cut gem.

As has been said, there is no limestone in this immediate vicinity, 

and these rubies were probably derived from an amphibolite or eclogite. The usual flat tabular form of the crystals is one that seems 

to be characteristic of the gem corundum when found in igneous rock.

The Cowee Creek rubies frequently contain inclusions, some of 

which are very minute, known to jewelers as "silk," and these give 

rise to a cloudiness or sheen in the polished gem. Rutile and menaccanite often occur in the rubies and greatly mar their beauty and value. 

Some gems that were 3 or 4 carats in weight have been cut, which 

were free from inclusions, of fine color, and transparent. A great 

many smaller ones have been cut that are perfect gems. In color and 

brilliancy these gems are equal to the Burma ruby, and if the percentage of the un.fl.awed transparent material increases but little this 

new field will be a worthy rival to the Burma field.

A considerable percentage of the transparent material is often very 

badly flawed by cracks due to parting, and by the inclusions of rutile 

or menaccanite, so that the percentage of perfect stone from this 

mine is small. This, however, is true of the rubies from the Burma

field, for a large proportion of the rubies on the market to-day are 

usually more or less flawed with the parting cracks.

The pleochroism exhibited by the Cowee rubies is very marked, some 

of them being a very rich pigeon-blood red in the direction of the vertical, axis that is, looking down upon the basal plane and changing 

to an almost pinkish-white color when viewed at right angles to this 

or looking through the prism. The pleochroism which nearly all the 

deep-colored varieties of corundum gems exhibit is one of the- means 

of identifying a corundum gem; this often interferes with the cutting. 

 The ruby crystals 1 from the Cowee Valley show a very wide variation in their development. Although many of the crystals are so 

striated that no crystallographic measurements were possible on the 

reflecting goniometer, the faces were readily identified by means of 

the contact goniometer. On some of the crystals the faces were bright

1 Am. Jour. Sci., 4th series, Vol. VIII, 1899, p. 379.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 180 PL. Ill

10

RUBY CRYSTALS FROM COWEE VALLEY, MACON COUNTY, N. C.
VRATT.] COBUNDUM GEMS. 43

and .smooth, making them well adapted, for measurement on the 

reflecting goniometer. These crystals are shown on PL III.

In the crystals examined two common habits were noticed; one is 

shown in figs. 1 and 2 of PL III, and is a combination of the base c 

(0001) and the unit rhombohedron r (1011); the other is represented 

by figs. 3-t> of PL III, where the prism a (1120) is very prominently 

developed. The rhombohedral crystals vary from those in which the 

base and the rhombohedron are disproportionately developed, the base 

having a diameter of .1.2 nun. and the rhombohedron of only 1.5 mm., 

to some (fig. 1. of PL III) in which the base and the rhombohedron 

are nearer one size. . The majority of these crystals have, however, 

the base more largely developed, thus giving the crystals a flat, tabular appearance. This rhombohedral development is very similar to 

the sapphires from Togo Gulch, Montana, described on page 52. l

On some of the prismatic crystals the prism reaches a'length of 

nearly 15 mm. in the direction of the c axis, and has the rhombohedron 

r but slightly developed (fig. 3 of PL III), while on others the prism 

is very short and the rli.ombolied.ron. is sometimes Avanting, as represented in figs. 4 and 5 of PL III.

Another habit of these crystals is shown in figs. 7 and 8 of PL III, 

where the pyramid n (2243) is well developed. This face Avas identified by means of the contact goniometer, the measured angles approximating closely to those calculated. The usual form of these crystals 

is shown in fig. 7 of PL III, where the faces c (0001), a (1120), r (1.011), 

and n (2243) are nearly equally developed. On some of the crystals 

the prism is 'very prominent, being 8 mm. in length in the direction, of 

the o axis, Av.hi.le the pyramid is only 1.5 mm.; on others the pyramid 

is only very slightly developed. A feAV crystals Avere examined Avhich 

showed only the presence of the base, the rhombohedron, and the pyramid, as represented in fig. 8 of PL III. The crystals, measuring up 

to 7 mm. in diameter, were doubly terminated and nearly perfect in 

their development.

The crystals represented by fig. 7 of PL III are similar to those 

described by Bauer 2 from the Burma district, and are almost identical 

in form Avith the sapphire crystals figured by me, from Emerald Bar, 

Canyon Ferry, Meagher County, Mont. (p. 50).

Although both the basal and rhombohedron planes are very often 

striated, it is only on the basal planes that the striations are sharp and 

distinct and can be measured. The striations are parallel to the three 

intersections of the base c and the rhombohedron r as shown in. fig. 5 

of PL III.

A very common development that was noticed on nearly all the flat 

rhombohedral crystals and on many of the prismatic crystals is a

1 Also Ain. Jour. Sci., 4th series. Vol. IV, 1897, p. 424.

"Neues Jahrbuch fiir Min., Gaol., und Pal., Vol. XI, 189C, p. 208.
44 COKUNDUM IN THE UNITED STATES. [BULL. 180.

repeated growth on the basal plane of the rhombohedron. r (lOll) and 

the base c (0001), as represented in figs. 1-6 of PL III.

To illustrate better the variation in these growths, a series of 

drawings, figs. 9-14 of PL III, have been made in basal projection. 

In figs. 9 and 10 of PL III, which represent the more common development of these repeated growths, there is but one secondary rhombohedron and base, which sometimes has one of its rhombohedron faces 

a continuation of one of the rhombohedron faces of the crystal. 

Figs. 11 and 12 of PL III represent the repeated growths, the faces of 

which are separate and distinct from one another and from the faces 

of the main crystal. In the crystals represented by fig. 12 of PL III, 

the basal plane of the crystal has the appearance of being striated 

with triangular markings when the secondary growths are but slightly 

developed. In ftgs. 13 and 14 of PL III is represented a series of 

growths where a number of the rhombohedron faces coincide.

Some of the pyramidal crystals (figs. 7 and 8 of PL III) also show 

the development of the secondary growth of rhombohedron and base. 

The thickness of the rhombohedron of the secondary growth varies 

greatly: some are so thin that they appear like striations; some are 2 

mm. in thickness. A few crystals were observed on which there Avas 

a secondary growth parallel to the prism 1120. This same style of 

development has been described by Bauer 1 as occurring in the Burma 

rubies.

The sapphire crystals from Montana, described on page 53, are 

strikingly similar in this respect to the Cowee rubies. Among the 

most noticeable associated minerals of these Cowee rubies is a delicate 

rose-colored garnet of great brilliancy, to Avhlch the name rhodolite 2 

has been given. The rhodolite usually occurs in wate.vwo.rn pebbles, 

but it has been found in very small dodecahedrons, and Its close connection with the rubies in the small crystals of rhodolite inclosed by 

the garnet has already been mentioned.

The other accompanying minerals are: Quartz, rarely aspseudomorphous dodecahedrons; corundum crystals, of pale-blue, amethystine, 

and pink shades; spinel (pleonaste); gahnite, in octahedral crystals; 

chromite (rare); vutile; menaccanite; bronzite (transparent); tremolite; hornblende; lolite (colorless); cyanite; fibvolite; staurolite in perfectly transparent fragments of a garnet-red color; monazite in small 

crystals; zircon, small, brilliant crystals, and also the variety cyrtolite; pyrite; chalcopyrite; pyrrhotite; sphalerite; sperry Lite in minute 

crystals; and gold.

Much of the work that has been done in Cowee Valley has been in 

the nature of prospecting to locate the extent of 'the ruby-bearing 

gravel and if possible to locate the origin of the rubies themselves. 

No work was done in the valley during the past year, but it is stated

1 Loc. cit., p. 209.

2Am. Jour. Sci., 4th series, Vol. V, 1898, p. 294.
PR AIT.] CORUNDUM GEMS. 45

upon good authority that work will be begun again in the coming 

spring.

At the Mincey mine, Ellijay Creek, ruby corundum has been found 

from Avhich several small stones could be cut. This occurs at the 

same locality as the bronze corundum, described below.

Another locality that is worthy of mention, and one that gives some 

promise of making a satisfactory showing in course of development, is 

the so-called gem mine on the property of Dr. C. Griinshawe, of Montvale, Jackson County, N. C. Rubies of good color, from which a 

number of fine but very small stones have been cut, have been found 

in the gravels of the stream. Blue and yelloAv corundum of gem 

quality is associated with the rubies. By folloAving up the gravels the 

corundum was located in a small vein in the decomposed peridotite.

At the Cullakeenee mine, Buck Creek, and near Elf, on Shooting 

Creek, Clay County, N. C., masses of 

emerald to grass-green amphibolite are 

found, through which are disseminated 

particles of pink and ruby corundum, 

ranging in size from that of a pea to 

some as large as hickory nuts. The 

corundum is not of gem quality, but 

the combination of the green amphibolite and pink corundum makes very 

beautiful specimens, and if the rock is 

hard enough to admit of a good polish, 

this occurrence might furnish a decorative or ornamental stone of some value.

At the Mincey mine, on Ellijay Creek, 

Macon County, and about 2-^ miles 

northeast of Corundum Hill, there occurs a peculiar brown or bronze corundum, known locally as "pearl corundum," which shows distinct asterism, both by natural and artificial 

light, when the stone is cut en cabochon. In natural light these 

corundums all show a bronze luster and are somewhat similar to the 

cat's-eye, but in artificial light the star is more distinct. Most of the 

bronze corundum is in rough crystals, but some have been found that 

have the prismatic faces smooth and well developed, and these are 

often dark, almost black, in color.

Asterism lias been noticed in many of the rubies and. sapphires from 

'Cowee Valley and in a few of the sapphires from the Montana deposits. 

This asterism, according to \Ton Lasaulx, is sometimes produced by 

rifts due to the basal parting. These rifts, when examined with the 

microscope, are seen to be very thin, sharp, and rectilinear, and are 

parallel to the edge of the prism onto base.

In other cases asterism is undoubtedly due to the rutiie or other

FIG. 7. Corundum crystal, showing concentric hexagons on basal plane.
46 COKUNDUM IN THE UNITED STATES. [HULL. 180.

mineral that is inclosed in the sappllires, which intersect each other at 

angles of 60°, and form a "sagenite web" or similar structure.

On many of the corundum crystals, especially of the sapphire variety, concentric hexagons were observed on the basal plane, as represented, in fig. 7. The edges of the hexagon are parallel to the edges 

of the prism faces onto base, and the plane of the hexagon is parallel 

to the base. In a few of the transparent crystals this hexagon was 

observed as a web in the midst of the crystal, the plane of the Aveb 

being parallel to the basal plane.

ORIENTAL SAPPHIRES.

The finest sapphires that are known are found in Burma and Ceylon, 

and have the rich, deep-blue color for which the oriental stone is 

noted. Sapphires of a rich, velvety blue arid some very good stones 

of a lighter color have been obtained from Simla Pass, in the Himalaya Mountains. Siam has also produced some sapphires of very 

good color. The sapphire corundum from Australia is generally of 

an opaque, milky-white color.

NORTH QAROLINA SAPPHIRES.

No corundum gems were found in the United States until the 

opening of the Corundum Hill corundum mine at Cullasagee, Macon 

County, N. C., in 1871. This corundum is mined for abrasive purposes, but. in certain parts of the deposit crystal corundum is 

occasionally found that is of a decided gem character, and, again, 

many of the fragments of the corundum have certain portions that 

are transparent. A number of very handsome dark-blue sappllires 

from this mine are in the United States National Museum, one of 

which weighs a carat. ]

Yellowish and blue colors in the same specimen are rather common, 

and are sometimes sharply separated into consecutive bands, while in 

other specimens the colors merge into one another.

Sapphire gems of all the different colors have been found at Corundum Hill, and I have in my collection cut gems representing all these 

various colors. Many of them are, however, very small.

During the past ten years but few gems have been obtained from 

this mine, for the reason that the portion of the deposit from which 

these crystals were formerly obtained has not.been worked. In the 

alluvial deposits below this portion of the mine many handsome 

crystals can be obtained by washing the gravel.

The green sapphire, which is the oriental emerald, is one of the 

rarest of gems. The Corundum- Hill mine .is the only place in this 

country at which the emerald-green sapphire has been found, and it

1 Kunz: Gems and Precious Stones of North America, 1890, p. 40.
BULLETIN N0.180 PL. IV

GaleTi Yo$o rSu!c

idboro.fc. f f ^\\ '. __ .

G A I, I, A T

y pringhill J

_S^.___._..J._I._

WING LOCATION OF MONTANA SAPPHIRE DEPOSITS

BY

.JOSEPH HYDE PRATT

JUL.4USB1ENSCO.LITH N.Y

Scale 

20 50 MlJjE S

X1NDICATES SAPPHIRE DEPOSITS. 

3S»00.
PRATT.] CORUNDUM GEMS. . 47

occurs very sparingly here, although the yellowish and light-green 

colors are not uncommon. What is probably the finest known specimen of the oriental emerald in the world came from this mine, and is 

now in the Bement collection. It is a crystal. 4 by 2 by 1£inches; part 

of it is transparent, and several very fine gems could be cut from it.

At the Sapphire and. White water corundum mines, near Sapphire, 

Jackson County, N. C., fragments of sapphire of a fine blue color have 

been found, from, which small but good gems have been cut.

Associated with the green amphibolite rock near Elf post-office, 

Clay County, 1ST.. C., deep-blue sapphires have been sparingly found. 

These bear the same relation, to the amphibolite as the red and pink 

sapphire described on page 45.

MONTANA SAPPHIRES.

The only systematic mining that lias been undertaken for sapphires

is in Montana. Sapphires were first found in this State by miners 

who were washing the gravels of the bars on the Missouri River, to the 

east of Helena, for gold. These were first described in 1873 by J. Lawrence Smith, 1 but it was not until 1891. that actual.ininlng was begun. 

During that year a number of companies were organized to work these 

bars for sapphires.

These bars are located from 12-to 18 miles east and northeast of 

Helena, and have been followed for a distance of about 12 miles from 

Canyon Ferry down the river to .American Bar. At various intervals 

these bars have been worked for the sapphires and are designated by 

the following names, starting with the one that is farthest up the 

river: Emerald Bar, Cheyenne 'Bar, French Bar, Spokane Bar, Metropolitan Bar,' Ruby Bar, Eldorado Bar, Dana Bar, and American. Bar. 

The location of these bars is shown on the map (PL IV).

A few sapphires have been found as far down the river as Beartooth, 

but sapphires have not been found in large quantity below American 

Bar.

Above Emerald. Bar there have been no sapphires found on any of 

the bars, but in. the gravel of Magpie Gulch, less than a mile aboA^e 

Emerald Bar (at Canyon Ferry), many sapphires have been found 

by "miners who were washing the gravel for gold. No sapphires have 

been found in situ in this gulch, but Kun/ 2 has noted the occurrence 

of sapphires that were found in a dike of vesicular mica-augiteandesite which Avas about 6 feet wide and cut through the green 

slate below the gravels. In the gravel deposits at French Bar, about 

8 miles below Canyon Ferry, a narrow dike was encountered last 

summer, 8 to 6 feet in Avidth, that had greenish sapphires scattered 

sparingly through it.

This dike Avas encountered about 50 feet above the river and its

1 Am. Jour. Soi., 3d series, Vol. VI, 1873, p. 185. 

" Miu. Mag,, Vol. IX., 1891, No. 44, p. 390.
48 CORUNDUM IN THE UNITED STATES. [BUT., I,. 180.

strike as it cuts through the slate/is N. 10° E., the dip being about

4:0° W.

This rock is undoubtedly of the same character as that described 

by Kunz as occurring at Ruby Bar. From the occurrence of these 

two corundum-bearing dikes of andesite it would seem that the source 

of the sapphires found in the various bars along the Missouri River 

is a series of small parallel dikes with a slight northeast-southwest 

trend, like those described. As the sapphires are scattered so sparingly through these di'kes, the amount of decomposition and erosion 

that was required to liberate those that are now found in the gravels 

must have been simply enormous.

The beds of gravel in which the sapphires occur are from 10 to 50

FiG. 8. Spokano Bar sapphire deposits, Lewis and Clarke County, Mont.

feet thick and rest for the most part upon slate, in bluffs that rise 

nearly 50 feet above the river. At Emerald Bar the gravel beds are 

nearly 130 feet above the river and rest upon granite rock.

Most of the mining has been done at Spokane and Eldorado bars. 

The former locality is near the center of the sapphire deposits and on 

the west side of the river about 16 miles due east of Helena. In 1895 

these beds of gravel, which are 8 to 18 feet thick, were extensively 

mined by an English company known as the Montana Sapphire and 

Ruby Company. The gravels were washed by hydraulic methods and 

a great many gems were obtained, most of which were sent to England. This company also controlled or owned French Bar and Dana 

Bar on the west side of the river and Eldorado Bar on the east side.
PKATT.] COKtfNDUM GEMS. 49

It was reorganized in 1897 as an American company, known as the 

Eldorado Gold and Gem Company, with A. N. Spratt, of Oakland, 

Cal., president, and Frank Spratt, of Helena, Mont., manager. No 

work has been done at any of the bars by the present company. 

This bar is shown in fig. 8, the bluff rising from the river being 

30 to 50 feet high.

Directly across the river from Spokane Bar, but about three-fourths 

of a mile from, the river, is Metropolitan Bar, which has been worked 

during the summer of 1899 by different men who have staked out 

individual claims. The gravels are from 6 to 20 feet thick, and are 

washed in hand rockers, the water being obtained from shallow wells. 

Several of the claims are owned by Robbin Bird, Charles Johnson, 

and John Durraut, of Helena, Mont.

Above Spokane Bar, French Bar, Cheyenne Bar, and Emerald Bar no 

regular mining has been done during the last few years, but frequently

different persons have worked in the old drifts for a few days at a 

time, washing by hand the gravel obtained.

A large part of the work done at Emerald Bar has been under ground, 

by means of shaft and drifts. Henry Crittenden, of Canyon. Ferry, 

has done a large part of the work here, and still controls the deposits.

Below Spokane Bar, at .Dana Bar, Eldorado Bar, and American Bar 

there was no mining for sapphires during 1899.

Most of the. gems that have been obtained from these bars during 

1899 have been put on the market through the Helena Lapidary 

Company, of Helena, Mont., of which William Knuth is manager. 

Mr. Kuuth has done considerable work on these bars, and has been 

instrumental in the development of the Montana gem fields.

As mining investments these sapphire deposits have not thus far 

been financially successful, partly on account of the heavy capitalization of the companies who have bought the mines and partly on 

account of the color of the stones. They are, for the most part, of a 

pale-greenish or greenish-yellow color, and do not command a very 

high price in the market. Occasionally pink and yellow ones have 

been found that have cut good gems. Stones approaching a red. or 

blue color are, however, extremely rare.

There are still a great many sapphires in the gravels that have not 

been worked, but on account of their color it is rather doubtful 

whether under the most favorable conditions it will pay to mine them.

The crystals from all these bars show the same development, and 

are prismatic in habit. The prism, a (1120), is always present, and 

is usually in combination with the base, c (0001), and the unit rhombohedron, r (IQll), as represented in fig. 9, A. Some of the crystals 

have the prism very short and the rhombohedron is wanting, giving 

the crystal a very tabular appearance (fig. 9, J5). A pyramid of the 

second order, n (2243), was observed on some of the crystals in addition 

to the base and unit rhombohedron, and is represented in fig. 9, C.

Bull. 180 01 4
50 OOKUKDWM THE UNITED STATES.

The crystals are usually rough and more or less striated, so that no 

measurement could be made upon the reflecting goniometer, but sufficiently accurate measurements could be obtained with the contact 

goniometer to identify the faces.

The largest crystal that has been observed from any of these bars 

was one from Eldorado Bar that was nearly an inch long and threeeighths of an inch in diameter.

A repeated growth was observed on some of these crystals, but not 

in the variety of forms seen in the Cowee rubies (p. 43) and the Yogo 

Gulch sapphires (p. 52). Only one form of growth was observed, represented in fig. 9, A, which is a combination of the unit rhombohedron 

and the base.

Since the discovery and mining of sapphires from the Missouri 

River bars sapphires have been found at three other localities in Montana at Rock Creek, Granite County; at Cotton wood Creek, Deerlodge County; and at Yogo Gulch, Fergus County.

The first two localities are about 80 and 30 miles southwest of those 

on the Missouri1 River, and the last one is about 80 miles to the uorth-

.4 B C 

FIG. Si. Sapphire crystals from Missouri River bars, Montana.

east. From these sapphire deposits stones of deeper colors have been 

obtained, those from the first two being of all colors from blue to red,

while those from the last are all blue.

ROCK CREEK SAPPHIRES.

For information concerning the sapphire deposits of Rock Creek, I 

am indebted to Mr. William Knuth, of Helena. All the sapphires 

that have thus far been found in this section are in the gravel deposits 

on the West Fork of Rock or Stony Creek, in the southern part of 

Granite County, about 35 miles southwest of Phillipsburg, the county 

seat, and 30 miles nearly west of Anaconda, Deerlodge County. 

(PL IV.)

The sapphires are found in rather a limited area, which is bounded 

roughly by the gravels of Cold Creek, Myers Creek, tributaries of the 

West Fork of Rock Creek, and that portion of Rock Creek lying 

between them.

These gravels were extensively worked during the summer of 1899, 

principally by William Knuth, of Helena, and William Moffitt, of 

Phillipsburg. Altogether about 200,000 carats of rough sapphires
PBATT.] ' COEUNDUM GEMS. 51

were obtained. Of these about 12,000 carats are fit for cutting. In 

color they are much more varied than those from the Missouri .River 

bars, and the prevailing color, which is greenish to bluish green, is 

deeper. No deep-blue sapphires like the oriental stones have been 

found, but paler blue ones have been obtained, from which very 

handsome' sapphires 2 or 3 carats in weight' have been cut. Some 

of the finest yellow sapphires (oriental topaz) that I have ever seen 

have been found at Rock Creek. One of these weighed close to 2 

carats when cut. Pale green and bluish green are among the common 

stones, some cutting gems of 5 to 8 carats in weight. A number of 

beautiful pink sapphires have also been found.

Few red and ruby-colored crystals have been found and none that 

would cut a gem over a twelfth of a carat in weight. These colors are 

extremely rare in the Montana sapphire deposits.

The crystals and fragments of sapphires that are found in these 

gravels do not show as much abrasion as those from the Missouri 

River, probably because they have been carried a shorter distance 

from where they originated.

In habit the crystals are very similar to those already described 

from the Missouri River, and fig. 9 will also illustrate very well the 

character of the Rock Creek crystals. One type that is very noticeable is a short prismatic crystal, whose diameter nearly equals its 

length. A parallel growth on the basal plane is only occasionally 

observed, and is composed of the basal plane and unit rhombohedron.

No sapphires have as yet been found in situ, but a few have been 

found in the gravels that were embedded in the original matrix. Mr. 

Knuth, to whom I showed a specimen of the aridesite containing sapphires from French Bar, said that it very closely resembled the small 

fragments of rock carrying sapphires that he had found at Rock 

Creek. It is not at all improbable that these sapphires originated 

in the same type of rock as those of the Missouri River and that 

small, dikes of audesite will be found in the divide between Myers, 

Cold, and Quartz creeks. A very few sapphires have been found on 

Quartz Creek.

While the sapphire gems from Rock Creek do not command so high' 

a price as the ruby and the deep-blue sapphires, and are regarded more 

as fancy stones, they are coining to be quite highly prized, by many 

who are acquainted with them. As yet but few of the Rock Creek 

sapphires have been put on the market except locally at Helena, and 

it seems tome that it can be confidently predicted that these sapphires 

will become important in the jewelry trade when they are once known.

COTTONWOOD CEEEK SAPPHIRES.

The sapphire deposits on Cotton wood Creek are in Deerlodge County, 

about 30 miles southwest of Helena and 10 miles east of Deerlodge, 

the county seat. . There has not been a great deal of work done on
52 CORUNDUM IN THE UNITED STATES. [BULL. 180.

this creek, so that the extent of the sapphire-bearing gravels is not 

known. The sapphires are similar in character to those of Rock 

Creek, but they are apt to be of lighter color and. not of such a 

variety of colors. What little work was done on the creek during the 

past summer was by Franz Cobalt, of Helena, and according to him 

there were but few sapphires taken out of the gravels. Future development at this locality may show these deposits to be of considerable 

importance and extent.

TOGO GULCH SAPPHIRES.

The sapphires that are the most widely known and that have 

attracted the most attention have been obtained in Fergus County 

near the entrance of Togo Gulch, on the Togo Fork of Judith River. 

This locality is on the eastern slope of Prospect Ridge of the Little 

Belt Mountains, about 75 miles northeast of Helena and 15 miles a 

little south of west of Utica, which is the nearest town, and which is 

on the Judith stage line. The sapphires were first found in the gravels of Yogo Fork, and in following these up the creek their original 

source was located in dikes that extend across the county for a mile 

and a half. 1

There are two parallel dikes about 800 feet apart, with a general eastwest trend, which vary in width from 15 to 75 feet. The mineralogical composition of the rock shows that it has a close affinity with 

minette and shonkinite, as described on page 28.

The alluvial deposits below these dikes have been pretty thoroughly 

worked for the sapphires, and mining operations are now confined 

almost entirely to the dikes themselves. These dikes, the upper portion of which is thoroughly decomposed, have been worked by means 

of open cuts, the limestone making fairly firm walls. By hydraulic 

processes the decomposed rock was readily broken up and washed 

into sluice boxes. As the mining extended deeper the rock was much 

less altered and it was necessary to leave a great deal of it exposed to 

the atmosphere from one season to the next, before it could be broken 

up and run through the sluice boxes. At a number of points the 

almost perfectly fresh rock has been encountered, and from this it 

will be a difficult problem to separate the sapphires. The percentage 

of sapphires in the rock is small and if it were the unaltered rock that 

had to be worked for them the deposit would not be of economic 

importance.

The sapphires occur embedded in this rock in distinct crystals from 

less than a millimeter in diameter to some that were over 15 mm. 

Their color, as far as I have observed them, is always a blue, varying 

from light blue to a very few that showed the dark blue of the Ceylon 

stone. The prevailing color is a bright blue. 2

1 The geology of the district and a full description of the mines and workings, by W.H. Weed, 

will be found in the Twentieth Aun. Rept. U. S. Geol. Survey, Part III, 1899, pp. 454-460.

2 Kunz: Am. Jour. Sci., 4th series, Vol. IV, 1897, p. 420.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 180 PL. V

JC

13

14

SAPPHIRE CRYSTALS FROM YOGO GULCH, FERGUS COUNTY, MONT.
PBATT.] . COEUNDUM GEMS. 53

While the color of these sapphires .is not as dark as the highly-prized 

Ceylon stones, they show a richness and brilliancy not equalled by the 

oriental stone. They not only show a strong rich color by transmitted, 

light, but their color is almost as good by reflected light. Then 

again, while many blue sapphires make beautiful day stones but are 

dull at night, the Yogo sapphire is a very brilliant night as well as 

day stone.

The crystallography of these sapphires is markedly different from 

that of the sapphires of the Missouri bars and Rock Creek (page 50). 

The latter all show a prismatic development, while the former are all 

rhombohedral crystals, none of which show the presence of any prism 

face. 1

The crystals are etched and striated to such a degree that no crystallographic measurements on the reflecting goniometer were possible; but sufficiently accurate angles were obtained with the contact

goniometer to permit the identification of the faces. The only two 

faces that could be identified Avere the base c (0001) and the rhombohedron x (3032) which is a new face for corundum. On one crystal 

two very small faces were observed which were too small to be measured with the contact goniometer, but were probably the faces of a 

pyramid of the second order.

In determining the rhombohedron, ten or more independent measurements were made of cf\x. These varied from 66° to 68°, but 

approximated closely to 67°, which agrees very well Avith the calculated 

value, 67° 3', for 0001A3032. . .These crystals are represented on PL V.

The crystals are developed, as shoAvn in figs. 1, 2, and 3 of PL V, 

the prevailing type being like fig. 3 of PL V. The crystals vary from 

those Avhere the base is very largely developed, having a diameter of 

8 mm., Avhile the rhombohedron is only 1 mm., to those that have the 

base and the rhombohedron equally developed (fig. 1 of P1..V). Where 

the faces are more equally developed, the rhombohedral faces are 

generally rounded.

The basal plane often shows characteristic striations which are parallel to the three intersections of the base c and the rhombohedron 

x, as shoAvn in fig. 4 of PL V. These lines are sharp and distinct and 

on the very flat crystals can easily be measured when examined under 

the microscope. The rhombohedral faces are very roughly striated 

Avithout shoAving any distinct parallel lines.

One very, common development of these crystals is a repeated growth 

on the basal plane of the rhombohedron x (3032) and the base c (0001), 

as represented in fig: 2 of PL V. These growths are exceedingly 

varied, as is sho\vn in figs. 11-14 of PL V, where they are drawn 

in basal projection. In fig. 11 of PL V there is but one secondary 

rhombohedron and base, Avhich has one of its rhombohedron faces 

a continuation of one of the rhombohedron faces of the crystal.

1 Am. Jour. Soi., 4th series, Vol. IV, 1897, p. 424.
54 CORUNDUM IN THE UNITED STATES. [BULL. 180.

Fig. 12 of PL V represents a repeated growth, eacli face of which is 

entirely distinct from the faces of the main crystal. In .fig. 13 of 

PL V there are represented two, and in fig. 14 of PL V a series of 

such growths, where a number of the rliombohedral faces coincide. 

These growths occur most frequently on the flat crystals. The 

thickness of the rhombohedron rarely reaches 1 mm. and often they 

are so thin that they appear like striations.

This repeated growth is very similar to that described as occurring 

on the Cowee rubies (p. 43). . Bauer, 1 in an article entitled " Ueber 

das Vorkommen der Rubine in Birma," has described this same style 

of development as occurring on the Burma rubies, but it is not so 

general as on the Montana corundums.

Etching figures. 2 The etching figures .which were observed on 

nearly all the crystals examined were on the basal plane. The figures are very perfect, and although .showing many different forms, 

they all have a rliombohedral symmetry. Fig. 5 of PL V represents 

the common etching figure, which is a rhombohedral depression terminating in a point. The edges of the depression are sharp and well 

defined, as are also the intersections of the rhombohedral faces of the 

depression. These rhombohedral faces were smooth and gave fair 

reflections of the signal on the reflecting goniometer. In measuring 

them the entire crystal except the depression to be measured was covered with a thin coating of wax. Two different crystals were measured, which gave for rhombohedron on rhombohedron 22° 30'; this 

corresponds to the rhombohedron 1017, for which the calculated value 

is 21° 50'. Figures of the same style were observed whose edges were 

parallel to those of the negative rhombohedron; these, however, are 

not common in isolated forms.

Another common form is represented in figs. 7 and 9 of PL V, where

the depression is bounded by the basal plane, which at times is so

large that the rhombohedral plane is hardly visible. Fig. 6 of PL V 

represents etching figures, where, on the basal plane of a shallow 

depression, there is one additional etching figure and sometimes two. 

These second etching figures are like the common ones shown in fig. 5 

of PL V. The outer rhombohedral contour of these figures is generally rounded. This is also usually the case with the deeper 

depressions.

Often the etching figures are intergrown, fig. 8 of PL V, and when 

many of these occur together they have the appearance of raised 

figures rather than of depressions. This raised appearance is veiy 

striking when there is a combination of the plus and minus rhombohedron in parallel position and without overlapping, fig. 10 of PL V.

The figures vary considerably in size, but most of them are near 

1 mm. in diameter. A few were observed that were nearly 2,mm. in 

diameter.

1 Neues Jahrbuch fur Min., Geol. und Pal., Vol. XI, 1896, p. 209.

2 Am. Jour. Sci., 4th series, Vol. IV, 1897, p. 426.
 GEOLOGICAL SURVEY BULLETIN No. 180 PL. VI

MAP SHOWING

^ LOCATION OFPKRIDOTITH ROCKS

Came&yille AND

CORUNDUM LOCAIJTIKS

IN

NORTH CAROLINA AND GEORGIA

BY

.JOSEPH HYUE PRATT 

19OO.

Scale

/ Pendotite

Talc and ohlorite schigts 

Corundum in basic magnesianrocks 

Corundum in gneiss or schist.
CORUNDUM IN NORTH CAROLINA. 55

Bauer' has described etching figures that he observed on the base 

0001 and the pyramid 2243 of the Burma rubies. Those on the base 

are similar to the figures iu fig. 5 of PL V, except that the outside 

contour of the rhombohedrou is rounded.

These sapphire deposits are now controlled by the New Mine Sapphire Syndicate of Utica, Fergus County, Mont., and London, England, of which Mr. George A. Wells, of Great Falls, Mont., is president. Mr. S. S. Hobson, of Lewiston, Mont., one of the directors of 

the company, states in a recent letter that 130,000 carats of cuttable 

material were taken out last season. Besides this there is a large 

amount of very small crystals and badly flawed larger crystals that 

are not capable of being cut into gems and that are sold by the 

ounce. The largest rough stones that have been, found weighed 11 

to 12 carats, and from these were cut gems weighing 5 to 6 carats. 

One of .the better stones taken out the season of 1899 weighed 4 carats

when cut and is valued at over $75 a carat. All of the material is 

shipped to London.

That the American gems are be ing appreciated :is shown by the large 

orders that are received for them from Paris, London, and New York.

CORUNDUM.

Under this head are included all the translucent to opaque varieties of all colors, subdivided into block, crystal, and sand corundum. 

While a sharp line can be drawn between corundum and emery, no 

such distinction can be made between corundum and sapphire, for 

many pieces of the former are found that have transparent portions. 

Many sapphire gems have been found in masses of corundum that 

were being mined for abrasive purposes.

In the following descriptions corundum deposits have been taken up 

by States in the order of supposed importance. Many of the beds 

are briefly noticed, but the larger and more important deposits are 

described in detail.

NORTH CAROLINA.

Most of the corundum localities in North Carolina are, in a general 

way, indicated on the map (PI. VI), except the very few that are east 

of the Blue Ridge. In the following descriptions only those deposits 

have been considered which have been mined for corundum or which 

hold out a promising prospect for the mineral.. These will be taken 

up by counties, the more important ones first.

MACON COUNTY.

Corundum was first discovered in this county in 1870 af what is 

now known as the Corundum Hill mine, and mining was begun here 

about a year later. This mine has become one of the most important

1 Loc. cit., p. 2ia
56 COKUNDUM IN THE UNITED STATES. [BULL. 180.

corundum deposits in this country. It is situated about 8 miles southeast of Franklin, the county seat, on the northeast side of Cullasagee 

Creek, a tributary of the Little Tennessee River.

The corundum found at this mine occurs in peridotite rock, and 

this has been worked very extensively, especially near the contact of 

this rock with gneiss. PL VII gives a general view of this peridotite 

formation, and shows to" a certain extent the number of openings that 

have been made in it. The hill is about 350 feet high, the summit 

being about 500 feet above the level of Cullasagee Creek. Fig. 10 is

Dunite. 

FIG. 10. Map of the peridotite formation at Corundum Hill, Macon County, N. C.

a topographic map of this same peridotite formation, and shows the 

location of the various mines. The formation is a rather blunt lensshaped mass of the dunite variety of peridotite, and has about 10 

acres of surface, over most of which the rock is exposed. As is seen 

from this map, most of the mines are located near the contact of the 

dunite with the gneiss or schist, and follow contact veins of corundum. A number of dunite veins have been worked within the formation, but with the exception.of the one marked " Shaft" on the map, 

they have all soon pinched out.
BULLETIN NO. iso PL. vn

DOTITE FORMATION AT CORUNDUM HILL, MACON COUNTY, N. C.
U. S. GEOLOGICAL SURVEY

THE BIG VEIN BETWEEN THE PERIDOTITE AND THE GNEISS AT CORUNDUM HILL, 

MACON COUNTY. N. C.
VRATT.] CORUNDUM IN NOETH CAROLINA. 57

Most of the mining lias been done on the sonth side of the formation, where was encountered what is known as the Big vein. This 

was first mined by means of open cuts and later by tunnels, the last 

one being about 300 feet below the summit of the hill. PI. VIII is a 

view of the entrance to this tunnel, and shows the peridotite rock on 

the left and the gneiss on the right beyond the cut. For nearly the 

whole distance of the southern boundary of the dunite formation a cut 

has been made following the contour of the hill. This cut was sometimes wholly within the gneiss, at other times wholly within the peridotite, and again cutting directly on the contact. The tunnels are all 

to the left of the cut, and they have encountered corundum almost 

continuously for a distance of 1,280 feet, reaching nearly to the southeast boundary of the formation. PL IX is a view of the upper or 

southeastern end of this cut, showing the peroditite on the left and the 

gneiss and schist on the right. The upper part of this cut is known

as the Stanfield mine. A tunnel has been run into the hill near the 

contact, at the head of Avhich the vein of corundum is 8 to 10 feet wide. 

No work has been done at this mine for a number of years.

On the northeast side of this formation is what is known as. the Zeb 

Jones mine, where there was exposed (July, 1899) a bench of ore 25 

feet in depth and 2 to 5 feet in width, uncovered for a distance of 

50 .feet, which averaged very close to 50 per cent corundum. This 

vein carries what is known as "buckwheat" corundum, which, as its 

name suggests, is made up of small, irregular particles of corundum 

about the size of buckwheat grains.

Numerous dunite veins have been found and worked, but they can 

be mined profitably only when they are large contact veins, for the 

reason that they are very likely to pinch out after being worked for a 

short time.

From these various openings, collectively known as the Corundum 

Hill mine, block, crystal, and sand corundum ores have been obtained, 

all of which can be readily cleaned and will make a commercial product that can be used in the manufacture of any kind of corundum wheel. 

A small amount of garnet is occasionally found associated with the 

corundum in the vein along the southern contact, but this portion of 

the ore can be readily eliminated by hand cobbing at the mine. This 

is the only mine that produced any quantity of corundum during 

1899. It is now owned by the International Corundum and Emery 

Company, of New York, N. Y.

The water of Cullasagee River is utilized for the washing and 

cleaning machinery of the mill, Avhich is located about a mile and a 

half below the mine, at Cullasagee. A line of sluice boxes connects 

the mine with the mill, and all the corundum ore that can be readily 

broken to pieces is carried down to the mill in these boxes.

There are many outcrops of peridotite on Ellijay Creek, a few miles 

north of Cullasagee, and at many of them corundum has been found.
58 COBUNDTJM IN THE UNITED STATES. [mn,r,. 180.

The most work that has been done is at the Mincey mine, which is 

2 miles northwest of the Corundum Hill mine. At this locality a 

considerable quantity of corundum has been taken out, which was 

carried to the mill at Cullasagee and cleaned. PL X is a view of this 

open cut, which was entirely within the formation. Judging by the 

amount of corundum obtained and by that found near .the contact of 

the dunite with the gneiss, there are good indications of the existence 

of corundum in. quantity along the contact. The corundum that was 

obtained at this mine was hauled by wagons to the Corundum Hill 

mine, where it was cleaned. This property is owned by the International Corundum and Emery Company, of NCAV York, N. Y.

Between the Corundum. Hill and Mincey mines there is a bold 

outcrop of dunite on the Gray property, covering about the same 

surface as that at Corundum Hill. Although there has been no mining here, the little, prospecting*that has been done has shown corundum to be very thickly scattered along the .lower borders of the 

formation, .and many small pits.-that have been sunk within the formation have encountered corundum. This, in iny opinion, is one of 

the most promising prospects for corundum in'Macpn County.

A great many of the peridotite formations along Ellijay Creek have 

been worked a little at different times, and these are mentioned in the 

lists of corundum localities (p. S3).

Sheffield mine. This mine is in Cowee Township, about 7 miles 

northeast of Franklin, the county seat, just north of Cowee Creek. 

The corundum occurs here in ainphibole-schist, and is described 

on page 31. On account of the depth to which decomposition has 

extended, the solid rock Avas only observed in. the lower portions of 

the 87-foot shaft, so that nothing definite is known of this corundumbearing amphibole-schist. The corundum, which is pink in color and 

which occurs in oval-shaped nodules up to an inch in diameter, lias

been pretty thoroughly mined down to the hard rock. The corundum 

is of good quality, and some preliminary tests have shown that it is well 

adapted to the manufacture of the vitrified wheel. On account of the 

low percentage of corundum in the rock, it is not at the present time 

- a profitable corundum ore.

The saprolitic ore is readily cleaned, and furnishes a nearly pure 

commercial product. A small mill has been erected here. This property is owned by the National Abrasive Manufacturing Company, of 

New York, N. Y.

CLAY COUNTY.

Buck Creek or Cuttakeenee mine. This mine is in the Buck Creek 

Valley, about 20 miles southwest of Franklin, Macon County, andJJl 

miles a little north of east of Hayesville, the county seat of Clay 

County. These corundum deposits are associated with a compact mass 

of peridotite, covering about three-quarters of a square mile, the largest
U. S. GEOLOGICAL SURVE lULLETIM NO. 180 PL. IX

UPPER END OF BIG CUT AT CORUNDUM HILL MINE, MACON COUNTY, N. C. 

Peridotite is shown on the left and gneiss and sch'st on The right.
U. S. GEOLOGICAL SURVE ULLETIN (SO. 180 PL. X

OPEN CUT ON DUNITE VEIN AT THE MINCEY MINE, MACON COUNTY, N. C.
' CORUNDUM IN NORTH CAROLINA. . 59

mass that is known in the Appalachian belt. Fig. 5 (page 22) is a topographic map of this formation, and shows the relation of the ainphibolite to the peridotite and the location of the various openings that 

have been made for corundum. There has been but very little systematic mining for corundum in this locality, and most of the work 

has been in the nature of prospecting. Numerous cuts and pits have 

been made at a great many points on the formation, most of which 

have shown the presence of corundum. The principal work is at the 

east end of the formation, near the contact of the dunite with the 

gneiss, where a shaft 40 feet deep was sunk partially on the contact 

vein. A number of open cuts in this same vicinity have penetrated 

into the same vein. This vein is different from most of the corundum 

veins in the peridotite rocks, in that it is composed essentially of 

plagioclase feldspar and hornblende, which bear a similar relation to 

Qach other as the feldspar quartx and mica in the pegmatitie dikes. 

PI. XI, .A, is a general view of the Buck Creek formation, showing the 

shaft mine and the location of the contact vein that has been opened. 

With this exception all the pits and cuts that have been made are 

within the formation itself, and where they encountered corundum it 

was in small pockets, the remains of larger dunite veins. PI. XI, J9, 

shows one of these dunite veins. From the amount of corundum 

exposed by prospecting and the work done in the shaft, there is without doubt a large amount of corundum associated with these peridotite rocks, and if the mine were more accessible to the railroad it 

would offer one of the best corundum prospects in the country. At 

the present time, however, the nearest shipping point is Murphy, which 

is over 40 miles to the west. The nearest point on the Murphy branch 

of the Southern Railway is only 18 miles, to which a good road can 

be built that would not cost much more than the first 18 miles of the 

road to Murphy. Buck Greek offers ample water supply for running 

a mill sufficient to clean whatever corundum would be mined here. 

This property is also owned by the International Corundum and Emery 

Company, of New York. The ore is not difficult to clean, and, as far 

as can'be judged from a superficial examination, should make a commercial product that can be used in the manufacture of the vitrified 

wheel.

jBZtte j%&/e cortmakM??/ i^ftG^. Under this head are included the 

long bands of corundum-bearing quartz-schist that have been found 

in the southeastern part of the county and in the adjoining county of 

Georgia (Rabun County). Parallel bands of this corundum-bearing 

schist have been followed for a number of miles close to the summit 

of the Chunky Gal and the Yellow mountains. As is stated on page 35, 

the amount of corundum in this schist is probably not over 5 per cent, 

and with such a low percentage of corundum these rocks are not to be 

considered, at the present time at least, as a source of this mineral.
60 CORUNDUM IN THE UNITED STATES. [BUI^. 180.

There are four tracts included under this head, which are described 

below.

The Scaly Mountain tract is near the headwaters of Beech Creek, a 

prominent eastern tributary of the Tallulah River, on the southern 

and southwestern slopes of Scaly Mountain, at the elevation of about 

4,500 feet. The corundum-bearing bands of schist have been traced 

for the distance of about 2 miles, with a general strike of. N". 40° E. and 

with a dip approximately 20°-30° IsTW. Considerable prospecting has 

been done in tracing this band of schist, but experiments show that 

there is less than 5 per cent of corundum in this schist, although some 

specimens have yielded 12 per cent. The latter were probably pieces 

broken off along planes of lamination of the schist, while the rest of 

the piece from which they were broken off carried but little corundum.

The Foster tract is in Georgia, about 1£ miles from Scaly Mountain, and the State line forms its northern boundary. It is on both 

sides of Falls Branch, one of the smaller Avestern tributaries of the 

Tallulah River, and is about 3,500 feet above sea level. Here a number of pits have been made and samples of corundum have been 

obtained which have assayed on an average about 5 per cent of this 

mineral. There is more garnet associated with the corundum in this 

ore than in that from any of the other localities.

The Yellow Mountain tract is on the north of Scaly Mountain, on the 

northern slopes of the Yellow Mountains. No prospecting has been 

done here, and from the indications the ore is the same grade as at 

the other localities.

The Chunky Gal tract is at the summit and along- the western 

slopes of the Chunky Gal Mountains, near the headwaters of Sugar 

Cove Creek.. With a few interruptions, the corundum-bearing schist 

has been traced for over 2 miles, with a strike and dip approximately 

the same as on the other tracts. A number of pits and cuts have been

made, from which considerable ore has been taken out and tested, 

and the tests show the percentage of corundum to be practically the 

same as at the others.

The corundum bands of the schist in all the tracts vary considerably in width, some being not over a foot or two wide, while others 

are 18 feet. In these wider bands, however, there are apt to be bands 

of the normal schist. More or less garnet has been found associated 

with the corundum in all the schist, and if in any amount would have 

to be eliminated or it would prevent any commercial corundum 

obtained from these ores being used in the manufacture of the vitrified wheel.

From the extent of the corundum-bearing schist, there is undoubtedly a large quantity of corundum in this section, but the low percentage of corundum in the rocks makes it very questionable whether they 

can be profitably worked.

The Corundum Mining and Manufacturing Company, of Philadel-
U. S. GEOLOGICAL SURVE

A GENERAL VIEW OF THE BUCK CREEK CORUNDUM MINE AND PERIDOTITE 

FORMATION, CLAY COUNTY, N. C.

B DUNITE VEIN OF CORUNDUM IN THE PERIDOTITE FORMATION AT BUCK CREEK,

CLAY COUNTY, N, C.
PR ATT.] CORUNDUM IN NORTH CAROLINA. , 61

phia, Pa., has recently been organized to work the deposits on the 

Scaly Mountain and Foster tracts. The only mining that has thus 

far been done consists of an open cut extending 35 feet on the band 

of corundum-bearing quartz-schist. About 1,000 tons of ore have 

been taken out, a small portion of which lias been crushed and cleaned. 

The point at which mining was begun is on the southwestern slopes 

of Scaly Mountain at an elevation of nearly 4,500 feet. The crushing 

plant has been erected close to the cut. The cleaning mill is about 

2,000 feet lower on Scaly Mountain, the crushed -ore being conveyed 

thither in a flume.

No definite method of cleaning has as yet been decided upon. 

Experiments have been made with, jigs and a Bartlett table, but they 

have not proved very satisfactory. The garnet and magnetite in the 

ore are to be separated by the electro-magnet. No corundum has as 

yet been cleaned for the market.

JACKSON COUNTY.

Perhaps the most important corundum locality in this county is in 

the extreme southeastern portion! in the vicinity of Sapphire, extending over into the adjoining county, Transylvania. In this section 

there is a series of about 30 outcrops of pe.ridot.ite, which extend in a 

general, northeast-southwest direction. All these outcrops are small, 

and corundum has been found associated with many of them. The 

location and relative size of the larger of these outcrops and the 

places where corundum has been, mined are represented on the map, 

fig. 11. Most of this has been at the Bad Creek arid Socrates mines, 

but the greater part of the work done at any of them has been in the 

nature of prospecting.

At the Burnt Rock mine, which is located about 5 miles northeast 

of Sappliire, all the mining has been, done'within the peridotite formation, and about 10,000 to "1.2,000 pounds of corundum have been 

taken out. It is of good quality arid occurs in white crystals and 

knotty, nodules. The ore is free from garnet and can be readily 

cleaned. From the amount of work done here the indications are 

that there is a considerable quantity of good corundum associated 

with the peridotite near its contact with the gneiss. The mining at 

the Brockton mine was also within the peridotite, arid about the same 

amount of corundum was taken out as at the Bunit Rock mine. The 

corundum occurs in dull-gray crystals, which are easily cleaned and 

separated from the gangue. These two mines are in Transylvania 

County. Just below this mine, on the slopes of Poplar Ridge, a vein 

of corundum was exposed in October, 1900, by workmen who were 

making a new road. The corundum is massive, and gives good indications of occurring in quantity.

The little work that was done at the Sapphire mine shows a considerable quantity of white and gray corundum, often speckled with blue,
6.2 CORUNDUM IN THE UNITED STATES. [BULL. 180.

very similar to the corundum found at the White water mine, G miles 

south of the Sapphire mine. . The Socrates mine is about threequarters of a mile southwest of the Sapphire, in a bold outcrop of 

peridotite. The corundum is in small, knotty nodules and is easily 

cleaned. A contact vein was encountered, but little work was done 

to develop it.

The Bad Creek mine lias been worked more than any other in this 

section, and is located about three-quarters of a mile nearly south of 

Sapphire. The work done at this mine has been almost entirely on a

FIG. 11. Map of the peridotite areas in the vicinity of Sapphire, Jackson County, N.C., showing 

tho location of the different corundum miues.

contact vein which has been exposed for the distance of 130 feet and 

has been worked at one point to a depth of GO feet. The corundum 

ore that was encountered in this vein is of two distinct kinds; in one 

the corundum, is associated with garnet and hornblende, and in the 

other, which is free from garnet, the corundum is in a matrix of biotitemica. These two ores should always be kept separate, for the corundum can readily be cleaned and separated from the associated minerals 

in the biotite ore and will yield a product that can be used in the 

manufacture of the vitrified wheel; but the corundum can be separated only with difficulty from the ore that contains the garnet. Unless
TUATT.] CORUNDUM IN GEORGIA. 63

the garnet can be entirely eliminated this ore will not make a product 

that can be used for making the vitrified wheel. The vein has an 

average width of ' nearly 0 feet, and will carry from 15 to 20 per cent 

of corundum. All these mines just referred to belong to the Toxaway 

Company, Sapphire, N. C.

Corundum lias been found at a number of the peridotite outcrops 

between the Bad Creek and the Whitewater mines; and while this 

does not by any means indicate that there are large deposits of this 

mineral in these rocks, it does indicate, taking into "consideration the 

corundum deposits already found northeast and southwest of these, 

that there is a possibility of such deposits, and it makes this section 

a promising one for systematic prospecting.

GEORGIA.

The corundum localities of this State are shown on the map (PI. VI),

which also gives the general location of the peridotite formations that 

have been observed in this section. Although there is considerable 

peridotite occurring in the northern portion of the State, it is at but 

few places thus far that corundum has been found in any quantity, 

and these are at the extreme northern part, not far from the North 

Carolina line.

Georgia corundum is well known, and perhaps lias the best reputation of any on account of that obtained from the Laurel Creek mine, 

which, with the exception of the Track Rock mine, is the only one 

that has produced any considerable quantity of corundum. The 

peridotite formations are not so large as in North Carolina, nor are 

the corundum localities so numerous, and it is not probable that there 

is as much corundum in this State as in North Carolina, although 

the Laurel Creek mine may be superior to any one thus far located 

in North Carolina.

Z/awreZ Oy'eeTc ?)mt6.--This mine, which is owned by the International Corundum and Emery Company, is located at Pine Mountain, 

Rabun County, Ga., and is 18 miles from Walhalla, S. C., the nearest point on the railroad. At this locality there is a large outcrop 

of peridotite, covering several hundred acres, and along the contact 

of this with the gneiss large deposits of corundum have been found. 

Several openings have been made, some of .which have been worked 

very extensively. Fig. 12 is a topographic map of this peridotite formation, showing the general location of the cuts and shafts that have 

been made. As is seen from the map, the formation extends over 

two small hills, which, on account of their rough and barren nature, 

offer a sharp contrast to the surrounding country. There is a large 

open cut (1 in ng. 12) on the east side of the formation, which follows 

for the most part along the contact, is 200 feet in depth at the lower 

end, and gradually rises until at the upper end the surface is reached.
64 COBUNDUM IN THE UNITED STATES. [BULL. ISO.-

At its lower end this cut encountered what is known as the Big 

vein of massive corundum, the cut having followed on a contact 

vein of crystal corundum. PI. XII is a photograph of this cut, which 

shows the gneiss very distinctly on the left and the peridotite on the 

right, with the shaft house in the foreground.

The Big vein of massive corundum, for which this mine is noted, 

is at the foot of the south slope of the hill, and has been followed from 

the lower end of the cut (1, fig. 12) for a distance of over 300 feet, 

represented by the dotted lines, with the shaft house (4, fig. 12) near 

the western end. Although this vein is near the contact of the peri-

<{/» INTERVAL SO ff£T

FIG. 12. Map of the peridotite formation at Laurel Creek, Rabun County, Q-ti.

dotite with the gneiss, it is separated from it by a band of peridotite 

and a small vein of sand corundum. There is' some doubt whether 

the block of gneiss (2, fig. ] 2) is entirely surrounded by the peridotite or whether it penetrates the peridotite from the main mass of 

gneiss. From Avhat could be seen, and from information obtained 

from Mr. Andy Evans, foreman of the mine, it has very much the 

appearance of being entirely inclosed in the mass of peridotite. The 

Big vein, which has been worked by an inclined shaft 116 feet deep, 

with tunnels 300 feet in length running from this, has brought the work 

up to the block of gneiss just referred to, and, according to Mr. Evans,
ERIDOTITE-GNEISS CONTACT AT LAUREL CREEK, GEORGIA, 

Shaft house in foreground.
PRATT.] COKUNDUM IN GEOKGIA. 65

a little work was done farther to the east which showed the corundum 

vein to extend on. the south side of the block of gneiss, arid it is not 

at all improbable that this vein continues as represented by the dotted 

line 3. Open cuts on the east and west side of this block of gneiss 

have followed contact veins of corundum. PI. XIII, A, is a photograph of the peridotite formation near the cut on the east side. 

Little work has been done at Laurel Creek except on contact veins, 

the principal exception being a small dunite vein (6 in fig. 12) near 

the west end of the formation, from which considerable corundum 

was obtained, but the vein soon began to pinch out. PL XIII, j5, is 

a photograph of this vein, showing both the hanging and foot walls of 

peridotite. At 5, fig. 12, considerable work has been done, and some 

large ciystals, for which this mine is noted, were obtained here.

This is perhaps the most famous corundum mine in this country, 

and has furnished ore from which an exceptionally good commercial

product has been obtained.

It has not been worked since 1894, when the tunnels and shafts 

of the Big vein were cut off by the slipping of a large block of the 

peridotite formation, nearly a 200-foot cube. It is"that portion of the 

formation represented on the map (fig. 12) between the open cut (1) 

and the cut to the west of the block of gneiss (2).

Track Rock mine. The location of this mine is in the northeastern 

part of Union County, Ga., on the south side of Track Rock Gap. 

The corundum occurs in a peridotite formation, which is very much 

decomposed on the surface, there being very little visible but a mass 

of chlorite-schist containing more or less actinolite. A tunnel, having its upper end 75 feet below the surface, has been run in on the 

formation for about 200 feet, with short branching tunnels at several 

points. From the material cut through by the tunnel, which was 

examined by King, 1 of the Georgia geological survey, the rock was 

found to be an altered peridotite, made up of small grains of chrysolite 

. surrounded by actinolite, and containing many grains of magnetite. 

It may be that the original of this rock was the peridotite amphibolepicrite.

All the work that has been done at this mine has been entirely within 

the formation, and the best results would be obtained near the contact of this rock with the surrounding country rock.

Foster mine. This mine, which is located in the northeastern part 

of Towns County, Ga., just over the North Carolina line, has been 

described with the other mines occurring in this vicinity under the 

head of "Corundum in North Carolina," on page 60. The corundum 

occurs in a quartz-schist, and the property is owned by the Corundum 

Mining and Manufacturing Company, of Philadelphia, Pa.

' Bull. Geol. Survey Georgia No. 2, 1894, p. 93.

Bull'. 180 01 o
66 COKUNDUM IN' THE UNITED STATES. [BULL. 180.

SOUTH CAROLINA.

' In the northeastern part of York County, from 3 to 4 miles west of 

the' Catawba River, on the land between Allison and Crowder creeks, 

corundum has been found in a belt about 200 to .300 yards wide which 

skirts along the western slopes of Nannies Mountain. This localitj^ 

is about 12 miles northeast of Ybrkville, S. C., and 25 miles southwest 

of Charlotte, N. C.

Mining-operations have been carried on at two distinct portions of 

this belt, one a mile north of the summit of Nannies Mountain, on 

the property of Alexander Rickard. The work done here consists of 

a shaft about 35 feet deep, from which several drifts have been run, 

which penetrate what is probably a light-gray granite, but it is much 

decomposed and of a sandy constituency. The only solid material 

encountered were irregular masses of black cleavable corundum associated with muscovite mica. In the surrounding fields float corundum 

ranging in size from small particles to masses of several pounds in 

weight are abundant, and many tons of this have been picked up and 

shipped. 

A little to the west of the south end of Nannies Mountain, about 

1^ miles from the Rickard mine, there is a similar occurrence of 

corundum. There have been a number of shallow cuts, ditches, and 

pits made in prospecting for corundum, but apparently none was 

found in place. The corundum that was found is often wrapped in 

mica.

. The mode of origin of this corundum has not been determined, for 

up to the present time the exact nature of its occurrence is not definitely understood, as no exposure of the corundum can be seen which 

>shows its relation to the rock in which it occurs. Neither can it be 

stated whether it is to be found in quantity.

PENNSYLVANIA.

The corundum in this State, so far as can be learned, is all associated 

with the serpentine rocks in Chester and Delaware counties and occurs 

near the contact of this rock with the gneiss. Considerable feldspar 

(plagioclase) similar to that described from the Big vein at Buck 

Creek, N. C., is usually crystallized out with the corundum.

Corundum has been found more abundantly near Unionville, in 

Newlin Township, Chester County. It is found here in a mass of serpentine rock, with an average width of about 800 feet and a length of 

1 mile. A number of tons of corundum have been obtained from this 

mine, but during the last ten years little or no work has been carried 

on here. Associated with the corundum are tourmaline and spinel.

MONTANA.

Most of the corundum that has been found in Montana has been of 

the sapphire variety, but at one locality near Bozeman, Gallatin
U. S. GEOLOGICAL SURVE

A PERIHOTITE FORMATION AT LAUREL CREEK, GEORGIA.

E DUNITE VEIN OF CORUNDUM AT LAUREL CREEK, GEORGIA.
PRATT,] EMEKY. 67

County, a variety has been found that may upon development prove 

to occur in commercial quantity. While no tests have been made to 

determine the abrasive quality of this corundum, preliminary fire 

tests have been made which indicate that it is suitable for use in the 

manufacture of the vitrified wheel. Then, again, the percentage of 

corundum in the ore, simply judging from the hand specimens, is 

high enough to make this a workable ore if in sufficient quantity. A 

description of the rocks in which the corundum occurs is given on

page 30.

EMERY.

Until recently the only emery known to occur in the United States 

was that at Chester, Mass., and Peekskill, N. Y., the principal mining 

being done at the latter place. Emery has now been found in North 

Carolina in a very promising prospect. As is stated on page 9, emery 

is a mechanical mixture of corundum and magnetite, or sometimes 

hematite. From its striking resemblance to iron ore, especially where 

it is a mixture of corundum and magnetite and is therefore magnetic, 

both the deposits at Chester and Peekskill were first worked as iron 

ores, and it was not for some time that their real nature and vahie 

were understood. Since then the deposit at Chester has been Avorked 

continuously and extensively.

Spinel is sometimes associated with the emery and increases in 

amount until it is largely in excess of the corundum, and the ore 

.passes over into what might well be called a " spinel emery."

MASSACHUSETTS.

The only deposit of emery that has been found in this State is 

in the vicinity of Chester, where .the emery vein has been traced for 

nearly 5 miles. The vein is first encountered about 2 miles northwest of the village of Chester, in a ledge that projects into- Westfield River from its left bank. The vein can be followed almost 

continuously along the line of the strike south to a little east of 

.south. It extends across the east slope of Gobble (North) Mountain, 

drops down into and crosses the narrow valley of Walker Brook, and 

then rising, it crosses South Mountain and can be followed for over 

2 miles to the south. The map (fig. 13) shows the general position of 

this emery vein, the places that have been opened along it, and the 

location of the different emery mills. The emery occurs in an amphibolite, which lias been described on page 23.

Beginning at the southern end of the vein the first work has been 

done about half a mile north of where the vein disappears, at what is 

known as the Wright mine. About twenty years ago rather extensive mining was being carried on here, the work consisting of an open 

cut nearly 1,400 feet long that was worked to a depth of 6 feet at its 

southern end and about 30 feet at its northern, with probably an
68 COKUNDUM IN THE UNITED STATES. [BU1.T,. 180.

average depth of 20 feet for the entire distance. Emery varying in 

width from 3 to 20 feet was encountered throughout nearly the entire 

length of the cut.

This mine was reopened in 1899, a shaft 87 feet deep having been 

sunk on the vein near the southern end of the cut and drifts run out 

from this. Margarite is the most conspicuous accessory mineral, and 

specimens that can rarely be excelled have been found here.

Continuing nearly half a mile to the north on the vein and near 

the top of the mountain is the Melvin. mine. There is a shaft here 

40 feet deep, from which drifts are being run. This shaft is but 

1,250 feet from, the head of the upper tunnel of the Old mine, the next

one to the north. It is 

in this Old mine that the 

most, extensive work has 

been done. Fig. 14 is a 

cross section of its underground workings. The 

mouth of the lowest tunnel is but 8 feet above 

Walker Brook and 75 feet 

to the south of it. As is 

seen from the diagram, the 

emery does not occur continuously throughout the 

vein, but in pockets or 

chimneys which dip into 

the vein about 30° N. 

From the work already 

done these seem to hold 

this direction rather constantly, so that the pockets can be approximately 

located at a given depth. 

It was in the first chimney 

of emery (see map, fig. 13) 

that the beautiful specimens of diaspore, for which this mine is noted, 

were found.

North of Walker Brook and about 500 feet from the Old mine 

is the Macia mine, where a small amount of surface work has been 

done. Near the head of a small ravine a tunnel was started on the 

west of the vein to intercept it, but work was discontinued before the 

vein was reached.

The next opening is near the highest point of the vein on the 

eastern slope of Gobble (North) Mountain, about three-fourths of a 

mile north of the Macia mine, and is known as the Sackett mine. At 

this part of the vein there was a considerable quantity of magnetite

FIG. 13. Map showing the location of the eniery deposit 

at Chester, Mass.
PllATT.] EMERY. 69

that was practically free from corundum and was mined as an iron

ore. This mine was worked 

very extensively over twenty 

years ago, but had been, abandoned until 1899, when it 

was reopened. The old works 

were near the highest point of 

the vein, on the slope of the 

mountain, and were worked 

for about 30 feet. The new 

work was started 117 feet below the mine, and a tunnel 

from the east side was run 114 

feet to the vein. When this 

was reached a shaft and tunnels were started. At this in ine 

the corundum occurs in what 

might be called porphyritic 

crystals of a bronze color, 

which are from 5 to 15 ram. 

across. Here blue and white 

masses of corundum weighing 

several pounds ' have been 

found, and small, well-formed 

blue crystals are also frequent. 

A little north of this mine, in 

an old opening, a cross vein 

of chlorite was encountered 

which carried a great many 

almost perfect cubes of pyrite 

and radiating groups of black 

tourmaline.

The last opening on the vein 

where there has been any work 

is at the Snow mine, over a mile 

north of the Sackett mine. A 

small open cut was made that 

exposed the vein, 3 feet in 

width. Between these two 

mines and also from the Snow 

mine north to the river the 

vein can be followed almost 

continuously.

While the vein can be followed nearly the whole distance, the emery does not occur throughout its entire length, for it is
70 COEUNDUM IN THE UNITED STATES. [BULr,. 180.

often in a series of pockets that are frequently connected with each 

other along the strike by a thin streak of chlorite and have a general 

dip in the vein of about N. 30°. In the direction of the dip, however, 

the emery is more or less continuous. The width of the vein varies 

from a few feet to 10 or 12, with an average width for the emery of 

about 6 feet. This is the most extensive deposit of emery known in 

this country.

Emery has also been discovered in the vicinity of Huntington, Mass., 

but no development work has as yet been done.

NEW YOKK.

The emery deposits of this State occur associated with the norite 

rocks in Westchester County that have been described on page 26. 

Deposits of magnetite and emery have been found at a number of 

places 3 to 4 miles southeast of Peekskill. These deposits vary 

considerably in character, some being a nearly pure magnetite, others 

containing magnetite and spinel, and still others magnetite, spinel, 

and corundum. Those within a mile north and northeast of Crugers 

Station have been worked for iron ore, while those worked for emery 

are in the southeastern part of Cortland Township. The principal 

openings have been made on a ridge running north from Colabaugh 

Pond and it is here that the ore has been mined. While the iron ore 

and emery appear to be Arery rich it was found upon examination that 

there was more or less of a dark-green mineral mixed with magnetite, 

and this mineral was shown by Williams 1 to be the pleonaste variety 

of spinel. There is also considerable spinel in the emery, and even 

when this is quite abundant it can not be distinguished in the hand 

specimens from that in which there is almost none of this mineral.

At the emery deposits in the southeastern part of Cortland Township the percentage of corundum varies considerably at different 

openings, and it is sometimes observed in small blue, white, and colorless crystals. Associated with most of the corundum there is spinel, 

and considerable of the ore that has been mined for emery has contained little or no corundum and has been made up of magnetite 

and spinel. An ore of this sort would have most of the requisite 

properties of a true emery except the high degree of hardness due to 

the corundum; and when made up into a wheel it would not have 

the cutting efficiency of a true emery wheel. The spinel, which is 8 

in hardness (corundum being 9), would play the same part in this ore 

as corundum in the true, emery, and while not so hard as corundum 

it has the cutting qualities which would give the ore considerable 

value as an abrasive. For many purposes wheels made from this 

could be used fully as well as emery or corundum wheels and for 

some purposes they might be used to better advantage. The spinel 

would not interfere at all in the manufacture of a vitrified wheel.

1 Ain. Jour. Sci., 3d series, Vol. XXXIII, 1882, p. 194.
PHATT.] EMERY. 71

Some of the'ore that' has been rained here carries a very high percentage of garnet.

The analyses that have been made of this ore all show a high percentage of alumina, which was to be expected, as the spinel is an 

alumina mineral, (MgFe)O.Al2 03 , containing about 50 per cent of 

this oxide. An error is very often made in judging the percentage of 

corundum in an ore by calculating as corundum the total percentage 

of alumina obtained in a chemical analysis, which would represent, 

however, the alumina contained in all the aluminous mineral components of the ore.

Some of the ore at these mines is undoubtedly a true emery, but a 

considerable portion of it is a mixture of spinel and magnetite, which, 

while not a true emery, will make a useful abrasive. This whole ore 

body might be called a spinel-emery.

From what has been said regarding the occurrence of the emery in 

these Peekskill deposits, their pockety nature is what would be 

naturally expected and this has been characteristic of all the mining 

that has been done in this district.

 The Jackson Mills Company, of Easton, Pa., is now the largest 

miner in this section. It has leased the emery deposits on the land 

of Isaac McCoy, 3 miles southeast of Peekskill. Its principal work is 

on the summit of a hill about one-half mile south of McCoy's house 

and consists of an open cut 40 to 50 feet deep, 40 feet long, and 12 

to 20 feet wide. The emery ore is from 4 to 6 feet wide, but is 

broken up by bands of serpentine'and chloritic rocks. In some of 

the ore the corundum is very distinct, occurring in elongated bluish 

white .crystals up to 5 mm., long. This ore is very free from garnet.

Another deposit of emery has been encountered 50 feet below the 

summit, and still another 25 feet farther down. No mining has been 

done at either of these localities.

The ore is hauled by teams, to Peekskill, where it is shipped by rail 

to Easton, Pa.

On a hill 1 mile east of the McCoy mine H. M. Quinn, of Philadelphia, Pa., has mined on the land of John II. Buckby. Pockets of 

emery were encountered on the summit of the hill and at a number 

of points on its western slope, but they soon pinched out. About 50 

feet below the summit a face of rock 15 to 20 feet high and 40 feet 

across has been exposed. The only emery seen here is the remnant 

of a pocket.

As far as could be learned the emery deposits of the Tanite Company of Stroudsburg, Pa., are also leased. They are on the lands of 

Henry Heady, Oscar Dalton, and David Chase, and are for the most 

part similar to the deposits just mentioned. The ore on,the land of 

Henry Heady is composed largely of garnet, and a considerable portion of it has been shipped by the Tanite Company to their mill at 

Stroudsburg.
72 - CORUNDUM IN THE UNITED STATES. [BULL. 180.

NORTH CAROLINA.

While corundum has been known to occur in quantity in this 

State for over thirty years, emery has until recently only been known 

from one locality, and here the quantity was not apparently sufficient 

to be worthy of any development. This deposit has been described 

by Genth1 as occurring at the McChristian place, 7 miles south of 

Friendship, Guilford County.

During the past few years emery has been found in Macon County 

in what appears to be considerable quantity. Nothing definite can 

be stated regarding the rock in which it occurs, as it is greatly decomposed as far as it has been exposed by the excavations. It does have, 

however, very much the appearance of a decomposed basic magnesian rock. There are a number of small outcrops of this saprolitic 

rock about 5 miles southwest of Franklin, the county seat, and emery 

in varying quantity occurs at all of them.

These outcrops, as far as could be judged, are isolated and in no 

way connected with one another. They are lenticular in form and 

but a few hundred feet wide, the longer axis being sometimes two or 

three times this. While the general direction of the strike of these 

outcrops is nearly the same, they are not in even an approximate line 

as regards.one another. For nearly 15 miles south of these and following the valley of the Little Tennessee River small isolated outcrops 

of peridotite are numerous. The country rock through which these 

have forced their way is a hornblende-gneiss.

Considerable mining was done two years ago by Dr. H. S. Lucas, 

of Franklin, at the Fairview mine near North Skeener Gap, about a 

hundred tons of ore having been taken out and cleaned. The vein 

has been tapped at intervals for a distance of nearly 200 feet, good 

emery being encountered at each opening. All the 'work done was 

near the summit of Fairview Knob.

One mile N. 25° W. of the Fairview mine, on the southwest slopes 

of Dobson Mountain, another opening has been made for emery in an 

outcrop of the same rock on the land of J. A. Waldroop. A vein of 

emery ore was uncovered here that was 15 feet wide. No mining has 

been done here, all the work being in the nature of prospecting.

Emery has been found in similar outcrops on the lands of William 

Mann, three-fourths of a mile south, and of James Ledford, one and 

one-fourth miles S. 30° E. of the Fairview mine.

Preliminary fire tests were made upon the cleaned product of this 

ore, which proved it to be well adapted for use in the manufacture of 

the vitrified wheel.

METHODS OF MINING CORUNDUM.

In considering the methods used in mining corundum, it must be 

borne in mind that up to the present time it has been obtained in quan1 Bull; U. S. Geol. Siirvey No. 74, 1891, p. 30.
METHODS OF MINING. ' 73

tity onty where it has been associated with peridotite rocks. These 

rocks, as will be shown later, present certain difficulties which, if not 

overcome, will .cause considerable delay and danger in mining. The 

emery occurring in amphibolite presents these difficulties in only a 

slight degree.

Nearly all of the peridotite formations in which the corundum 

deposits occur are bold outcrops on. the mountain sides and hilltops, 

having almost perfect natural drainage. At all the localities where 

there has been no mining the little prospecting lias been usually by 

means of open cuts supplemented by tunnels. While at first mining 

by means of cuts may seem to be the most advantageous, it is soon 

found to be the cause of considerable extra expense. These cuts, or 

any other openings made over the surface of the peridotite, offer a 

much greater opportunity for surface water and frost to penetrate the 

mass of the rock formation. These rocks are more or less seamed or 

cracked, usually to the depth that alteration can extend, and thus 

offer opportunities for the infiltration of water. As most of the alteration products of this peridotite formation are slippery hydrous magnesium minerals, such as serpentine and talc, and as these are developed in the seams and cracks of the peridotite, anything that is done 

to disturb them Avill make them very liable to slip. At the Corundum 

Hill mine there are large masses of peridotite that have become loosened and gradually slipped down and closed up some of the tunnels, 

and there is constant danger that fragments of the rock will fall into 

the cuts and some of the tunnels. At the Laurel Creek mine, a mass 

of peridotite Avith soil, etc., nearly a 200-foot cube, has become loosened and slipped downward, effectually closing up the tunnel and 

shaft of the Big vein.

In. mining corundum associated Avith peridotite rocks it is therefore 

advisable not to break the surface of the formation any more than is 

absolutely necessary and to do no work at all along the contact by 

means of open cuts, but to confine the mining to a system of tunnels 

and shafts. This method of mining Avill-be found the cheapest in the 

end. Then, again, all the tunnels and shafts should be well timbered 

and the mine kept as thoroughly drained as possible.

A large amount of the material that must be handled is easily 

worked with pick and shovel, as it consists, of the crystals and fragments of corundum in the zone of chlorite and vermiculite. In those 

Areins in which, the corundum is associated Avith feldspar, as at Laurel 

Creek and Buck Creek, and those Avhere there is considerable am.ph.ibole or enstatite, as at Corundum Hill, blasting is necessary. Most of 

the corundum deposits in peridotite are so located that there need be 

but little hoisting of the ore for some time. By drifting from, a shaft 

at the upper end of a tunnel that has been run into the vein at the 

lowest level possible the ore can be removed Avith a minimum of hoisting'and the mine Avill be kept dry.

If the mill is located some distance from the mine and a line of
74 CORUNDUM IN THE UNITED STATES. [BULL. 180.

sluiqe boxes can be built, the more or less finely divided ore may be 

carried to it by means of these. In this way the ore is partially 

cleaned by the time it reaches the mill. This is the method employed 

at the Corundum Hill mine. , Where the corundum occurs in a gneiss, quartz-schist, or syenite, 

there should be no difficulty in mining by means of open cuts.

METHODS OF CLEANING CORUNDUM.

The difference between the commercial product and the ore as it 

comes from the mine is that the latter has been freed as far as possible of all impurities, so that the resulting product is or should be 

nearly pure corundum or emery. Most of the impurities are easily 

removed by conveying the crushed ore into boxes through which a 

stream of water runs, which is so regulated that the corundum readily 

settles to the bottom, of the trough and the lighter minerals are carried off. Before this, however, the crushed ore is sieved, and all 

that will not pass through a No. 12 screen is recrushed and passed 

between rollers until it is reduced to the desired size. This washing process will remove only the impurities that are entirely separated 

from the particles of corundum, but there are usually some of the 

impurities attached to the particles or grains that have to be removed 

by another process. The product is passed through a machine known 

as the screw or scouring machine, in which there is a coarse worm 

similar to the screw conveyer. This grinds out almost all of the impurities, and these are separated by again subjecting them to the 

washing, process. The final impurities are separated from the particles of corundum by means of a machine called the "muller" or 

"chaser " (see PI. XIV). The principle of this is to cause each grain of 

corundum to rub against another and thus wear away the adhering 

foreign substances. The machine consists of a shallow tub, in which 

are two hecTVy WOOden rollers which move around its circumference. 

The freshly ground corundum, on being thrown into these tubs is kept 

constantly stirred up and then pressed down by the rollers being 

passed over it. In this way the scouring motion is kept up between 

the grains. The impurities are thus gradually worn away and are 

carried off by a stream of water that flows continually through the 

tub. The corundum in the tub is kept stirred up by men with hoes 

or by plow-shaped iron blades in front of the wooden rollers. It 

usually requires from four to eight hours, according to the nature of 

the impurities that are attached to the corundum grains, to obtain 

a clean product.

There are two methods of drying this product, by either of which it 

is removed from the mullers and allowed to lie overnight on inclined 

floors. By one method this product is conveyed by elevator belts to 

the second floor of the mill and dropped vertically for a distance of 

20 to 30 feet down 'the stack of a furnace. At the bottom it strikes an
U. ?. GEOLOGICAL SURVE lULLETJN NO. 180 PL. XIV

A. CORUNDUM MILL AT CULLASAGEE, MACON COUNTY, N. C.

B. INTERIOR VIEW OF CORUNDUM MILL AT CULLASAGEE MACON COUNTY, N.
PRATT.] METHODS OF CLEANING AND USES. 75

inclined surface that is just above the flames of the furnace and slides 

down this surface into an iron box. By the other method the wet 

product is thrown in at the upper end of an iron cylinder, open at 

both ends, which revolves about a coil of steam pipes. One end of 

the cylinder is lower than the other, and the wet mass is alternately 

carried up by the revolving cylinder and dropped on the hot coil of 

pipes, and so gradually worked toward the lower end, where it is 

caught in a hopper and conveyed by elevator belts to the sizing room. 

Here it is automatically screened to the various sizes.

On PL XIV, A and J5, are views of the exterior and interior of the 

corundum mill at Cullasagee. In the foreground of B are the boxes 

in which the ore is first washed and just beyond these are the ran Hers.

Only within the last few years has any attempt been made to 

improve the methods of concentrating and cleaning corundum. There 

are now a number of companies that have installed complete concentrating mills, similar to those used in concentrating gold ores, but

modified to suit corundum ore. While all are using jigs for the 

coarser sizes of the crushed ore, some are using Frue vanners and 

others Bartlett or Wifley tables for the finer sizes. This method 

works very satisfactorily for concentrating the corundum, and if, 

during the crushing and rolling of the ore, the corundum is largely 

 separated from the associated minerals, a nearly cleaned product 

is obtained. It is necessary, however, .to subject the larger part of 

the concentrates to some process similar to that performed 'by mullers, 

to free the grains of corundum from other minerals attached to 

them.

A new machine the Hooper pneumatic concentrator can also probably be used to advantage in concentrating corundum ores.

Any other minerals that will be likely to remain with the corundum 

in the concentrates, as garnet, pyrite, etc., can undoubtedly be separated by means of the Wetherill magnetic concentrator. Unless these 

minerals are Unattached to the particles of corundum there will be a 

considerable loss of corundum by this separation.

USES OF CORUNDUM.

Corundum is used for only two general purposes, as gems and as an 

abrasive.

The varieties of corundum that are of value as gems have been 

described on page 39, and the many uses that are made of the cut 

stones in the jewelry trade are too Avell known to need more than a 

passing notice here. One use of the corundum gem that is perhaps 

worthy of notice is in supplying jewels for watches. In a recent 

notice from the Swiss agency of precious stones for watches, Aarburg, 

Switzerland, it said that 75,000,000 watch jewels are required annually. 

With the increase of production of gem corundum in this country a
76 CORUNDUM IN THE UNITED STATES. [BULL. 180.

great deal of the smaller fragments could and should be utilized in the 

manufacture of watch jewels.

Both corundum and emery are used in the manufacture of abrasive 

materials, and these are on the market in three forms, as wheels and 

blocks of various shapes and sizes, as emery paper, and as grains or 

powder. The last two need no further explanation,.but a description 

of the first is of importance.

The shapes of the corundum and emery wheels and bricks or stones 

are extremely varied, being adapted to all kinds of grinding. The 

principle of these wheels is the same as that of the rotary files, and 

as the points of a file become dull from using, so also do the grains or 

points of the emery and corundum in the wheel. In making a wheel 

it is necessary, therefore, to make it of such a temper or grade that 

when these grains become dull or rounded they will fall away or will 

be readily removed by a truing tool, leaving fresh, sharp grains 

exposed. The grade of a wheel depends upon the character of the 

work for which it is to be used, and the bond should .be such that it 

will wear away a little faster than the corundum or emery, and thus 

always leave the sharp edges ready for cutting. The greatest economy 

is effected when the bond does not wear away until the grains of emery 

or corundum have become rounded or dulled, thus permitting the 

wheel to do its greatest amount of work.

Before leaving the factory all wheels should be thoroughly tested to 

a higher strain than that to which they are to be subjected in actual 

use; as the wheels have to be run at a very high velocity in order to 

secure the greatest efficiency, there is at times but little reserve 

strength, and a sudden blow will often cause them to fly to pieces.

To give an idea of the number of different wheels that the larger 

emery-wheel companies are prepared to make, I can not do better 

than to mention what I saw and what was told me at the Norton

Emery Wheel Company, of Worcester, Mass. The wheels are manufactured for the special work for which they are intended, and vary 

in shape, in bond, and in grain of corundum. The sizes of corundum 

that are used are Nos. 12, 14, 16, 20, 24, 30, 36, 40, 50, 54, 60, 70, 80, 

90, 100, 120, 150, 160, 180, 200, and 6 grades of flour corundum. The 

bond has 26 degrees of hardness, represented by the letters of the 

alphabet, although a bond is seldom used softer than E or harder 

than M. There are 408 different sizes of circular wheels, so that the 

different grades of wheels possible are almost unlimited.

There are three types of wheels known to the trade, the vitrified, 

chemical, and cement, the names being derived from the process by 

which they are manufactured. In the manufacture of all, the corundum or emery used is in grains of uniform size, but varies with the 

grade of wheel that is to be made. The vitrified wheel is the most 

important, and most generally used, although for some work one of the
PRATT.] USES. 77

others is preferable, and for very large wheels the chemical is especially 

adapted.

VITRIFIED WHEEL.

In the manufacture of this wheel more care is necessary in the 

selection of the corundum, for.in the vitrifaction of the bond the 

foreign minerals containing water are very likely to cause the wheel 

to burst. The corundum grains are mixed thoroughly in a paste of 

prepared clay and other fluxes, and the mixture is then poured into 

paper molds .and set aside in a drying room until hard enough to be 

readily handled. When the molds are sufficiently dry, they are subjected to a dressing or trimming process and shaped to approximate 

dimensions on a potter's wheel or shaving machine, and are then 

further dried.

The excess of mechanical water having evaporated, they are then 

ready for the kilns. The kilns are cone shaped and the inside measurements vary from 12 to 20 feet in height and 10 to 18 feet in diameter. When the kiln is filled the entrance is closed and sealed and the 

fires are started. The temperature is allowed to rise slowly, until all 

the water of mechanical admixture and of crystallization in the foreign materials is driven off, when the temperature is raised to about 

3,000°, or to a white, heat, this heating process requiring several days. 

Where the foreign minerals mixed with the corundum contain water 

of composition that is driven off only at a very high temperature, the 

wheels are apt to be broken by this water coming off when the temperature of the kiln is raised to the fusing point of the clay. The 

clay and other fluxes fuse and form a porcelain setting for each grain 

or fragment of corundum, which makes a very strong bond. The kilns 

are allowed to cool very slowly, several days being required for this. 

The kiln is then opened and the wheels are brought to a lathe, called 

the "truing machine," where they are turned to the exact dimensions 

desired, the hole, is bushed to the exact size, and the wheel is then 

trued and balanced ready for shipping.

The heat necessary for the fusion in making the vitrified wheel 

apparently has no effect upon the corundum beyond a partial decolorization and the expulsion of the slight percentage of water in the 

corundum.

CHEMICAL WHEEL.

In this process, which is also called the silicate process, silicate 

of soda is used as the binding material. The silicate is thoroughly 

mixed with the emery or corundum and some drying material and 

tamped into molds. It is then subjected to an '' oven " heat for twentyfour hours, after which it is removed and finished according to the 

method -described above for the vitrified wheels after they are removed 

from the kilns. Wheels have been made by this process that were 

over 2,000 pounds in weight.
78 COKUNDUM IN THE UNITED STATES. [BOLL. 180.

CEMENT WHEEL.

In the cement wheel, shellac, rubber, linseed oil, and other substances are used as the binding material. This makes a soft wheel 

that is well adapted for roll and surface grinding when made with 

shellac, and for saw gummers and thin wheels when made with oils.

Although an examination of a corundum property may show the 

existence of considerable quantity of the mineral, no mining should 

be undertaken until satisfactory tests have been made upon the 

corundum to prove that it has those properties that will make it of 

value as an abrasive.

The value of a corundum deposit as an ore for abrasive purposes 

depends upon that property of the mineral which enables it to retain 

a sharp edge, known as a cutting edge, when it is crushed to grains. 

All corundums do not have this property, and while many exhibit 

this in the first stage of the crushing, the finer fragments and grains 

do not. This is more apparent when the corundum has been made 

into a wheel, for when first used the wheel may do good work, especially if it is a coarse-grained wheel, but as it wears away, the grains 

of corundum become rounded, instead of breaking to a cutting edge. 

In estimating the value of a corundum deposit, it is therefore very 

essential to determine the abrasive qualities of the corundum. 

Neither a chemical analysis nor a superficial examination of a corundum ore will determine its cutting qualities, and this can be obtained 

only by making the corundum into a wheel and testing it.

In estimating the value of .an ore it is also necessary to determine 

to what degree of purity it can be cleaned, or what percentage of the 

commercial product will be corundum, and also what will be the 

nature of the foreign minerals. A foreign mineral will always be 

softer than the corundum, and will to a certain extent reduce its

abrasive power. Beyond this, the presence of a small amount of

foreign mineral does not materially affect the value of the corundum 

for making a cement or chemical wheel, but is often the reason for 

discarding it in manufacturing a vitrified wheel, on account of the 

low fusibilnYy of the foreign substance. Garnet is perhaps the most 

objectionable mineral in a corundum ore, it being very difficult to 

separate it.from the corundum, because the specific gravity of the 

two is nearly the same. Corundum containing even a little of the 

garnet can not be used in the manufacture of the vitrified wheel.

OTHER USES.

Aii attempt has been made to use corundum as a source of aluminum, but on account of its refractoriness and the percentage of ferric 

oxide and silica that it often contains, and on account of the cost of the 

ore, this use has not been found feasible.
PIIATT.] COKUNDUM LOCALITIES. 79

The late Mr. Alfred E. Hunt, of Pittsburg, Pa., made the following 

statement: *

The real difficulty which we find in the use of corundum for this manufacture 

is the cost of the raw material as compared with that of native bauxites. In this 

item we include not only the price of the corundum as it has been offered to us, 

but also the expense of grinding it to an impalpable powder, which must be done 

before it can be used directly in the manufacture of aluminum, and the cost of 

preliminary chemical treatment for purification which latter operation, however, 

is also required for bauxite.

Corundum has also been used as the source of the aluminum in the 

manufacture of aluminum-copper and aluminum-iron alloys. In the 

manufacture of these the corundum, without undergoing any previous 

treatment, was charged into an electric furnace with a mixture of 

carbon and copper or carbon and iron, according to whether aluminum 

oronze or ferro-aluminum was desired. Since 1890, however, when 

alumina began to be manufactured at a comparatively low price, this 

artificial oxide has been used in the place of the corundum.

CORUNDUM LOCALITIES IN THE UNITED STATES.

Under this head are included practically all the localities in the 

United States at which corundum has been found, and if they have 

been described under the heading "Distribution of corundum" they 

are simply mentioned here. Regarding the other localities, the mode 

of occurrence is given in most cases, and also some idea of the extent 

and character of the corundum.

This list is probably not complete, but it represents all those localities that I have visited and those of which an authenticated record 

could be obtained. It is taken up alphabetically by States.

ALABAMA. 2

Dudley ville. Between this town and Perry Mills, Tallapoosa 

County, corundum has been picked up at a number of places in the 

soil, but none has been found in place. Peridotite rocks have been 

found in the vicinity, and it is not at.all improbable that the corundum 

was derived from these rocks.

Hanover. Corundum has been found sparingly in Coosa County 

in the vicinity of this town.

CALIFORNIA.

Plumas County. An interesting occurrence of corundum lias 

recently been observed in the vicinity of Meadow Valley. Cutting 

the serpentine rocks of the eastern slope of Spanish Peak at an elevation of about 4,100 feet, and !£ miles west-northwest of the Meadow 

Valley post-office, is a series of white coarse-grained dikes that are

1 Trans. Ain. Ins. Min. Eng., Vol. XX VIII, 1898, p. 875. 

» <?eol. Survey Alabama, Report, 1875, p. 85.
80 COEUNDUM IN THE UNITED STATES. [BULL. 180.

composed of 84 per cent of oligoclase and 16 per cent of corundum. 

The corundum is in crystals up to 2 inches in length and 1 inch in 

diameter, the general habit being pyramidal, and it is distributed 

rather irregularly through the groundmass of feldspar. This is a 

further illustration of the differentiation of a rock magma, supersaturated with alumina which has crystallized out as corundum. It is 

still uncertain whether these deposits of corundum will prove to be 

of commercial importance.*

COLORADO.

Chaffee County. Corundum crystals have been found at the Calumet iron mines in the mica-schists at their contact with intrusive dikes 

of diorite. R. C. Hills, geologist to the Colorado Fuel and Iron Company, writes that the ore occurs in a band of rock 6 inches to 2 feet 

thick that has been followed for a distance of 500 feet, and that it 

averages 40 per cent of corundum.

CONNECTICUT.

Litchfield. Corundum was found here associated with talc and 

pyrite in a mass of blue cyanite. Only surface specimens were found.

Norwich. In the vicinity of this place corundum was found sparingly with sillimanite.

DELAWARE.

Corundum has been found in this State in the serpentine rocks near 

the Pennsylvania border. The only locality definitely known is near 

Chandlers Hollow, in Newcastle County, about 2^- miles south of Concord, Delaware County, Pa. It has been found only in small quantity.

GEORGIA.

Acworth. Seven miles southwest of Acworth, Cobb County, there 

is a large peridotite formation which is entirely within Paillding 

County. From a pit sunk within this formation about 1,000 pounds 

of corundum were taken out. It is of poor quality, but makes handsome mineral specimens.

Bell Creek mine. This mine is 4 miles north of Hiwassee, Towns 

County, and the corundum, mostly of a pink color, occurs in a peridotite. The work done consists of a pit 12 feet square by 12 feet 

deep. Only a small quantity of corundum was found.

. Centralhatchee. At this place, Avhich is in Heard County, grayish, 

white, and blue corundum has been found in a matrix of hornblende, 

which is associated with basic magnesian rocks.

Douglas County. Blue corundum in a pale greenish cyanite.

Foster mine. The corundum occurs in quartz-schist. (See p. 60.)

Q-ainesvillc Beautiful specimens of red corundum have been found 

in the peridotite formation 1 mile east of Gainesville, Hall. County.

1 A. C. Lawson: Am. Geplpgist, Vol. XXVII, 1901, p. 132; J. A. Edrnan, letters from.
ntA-rr.] COKUNDUM LOCALITIES. 81

Habersham County. Corundum, lias been found as surface specimens at a number of localities in this county, and at one place in the 

peridotite formation. There have been no developments and there 

are no indications of any quantity.

Hamilton mine. The corundum, occurs in a pcridotite formation 

about 5 miles north of Young Harris, Towns County. No large 

quantity has been found.

Hog Creek 'mine. This mine is 2 miles a little south of west of 

Hiwassee, Towns County, but it lacks development. The corundum 

is associated with peridotite, and is pink, blue, and white.

Laurel Creek mine. In peridotite. (See p. 63.)

Monroe. Four and a half miles from Monroe, Walton County, on 

the farm of George W. Breedlove, black corundum has been found 

associated with peridotite rocks. Some little prospecting done here 

has been within the formation and some near the contact.

Pine Mountain, Rdbun County. In peridotite. (Seep. 63.) 

 Porter Springs. One mile southeast of this place (in. Lumpkin 

County) corundum has been found in'an ainphibolite, but there is no 

quantity.

Powder Springs. There is a considerable outcrop of peridotite in 

Cobb County, in the vicinity of Powder Springs, which offers a promising place for prospecting. A small vein lias been opened on the 

W. B. Turner farm.

Rabun G-ap. Several pounds of corundum have been obtained 

from the Beavett mine; it occurs in a peridotite rock.

Teltonmlle. One mile north, of this town, in Forsyth County, surface specimens of corundum were found which evidently originated 

in the quartz-schists of this region.

Stone mine. This mine, which is in the same general formation as 

the Track Rock mine (see p. 65), is in Rabun County. Only a little 

development has been undertaken and the prospect that the deposit 

may be valuable is not very favorable.

Tliomaston. Seven to 8 miles southwest of Thomaston, Upson 

County, considerable corundum has been found on the surface at the 

old Kelly farm. Some of the specimens of the corundum in the 

matrix indicate that it was derived from a mica-schist.

Track Rock mine. In. peridotite. (See p. 65.)

West Point. A short distance northeast of this town (in TroupCounty) corundum has been found sparingly in a narrow strip of 

peridotite. Apparently no large quantity.

MARYLAND.

Corundum has been reported to occur in the vicinity of Whitehall, 

but no definite information can be obtained that any has been found 

here beyond a stray surface specimen.

Bull. 180 01 6
82 CORUNDUM IF THE UNITED STATES. [BULL. 180.

MASSACHUSETTS.

Chester. Emery in aniphibolite. (Seep. 67.) 

Huntington. Emery in amphibolite. (See p. 70.) 

Pelham. Corundum in saxonite. (See p. 19.)

MONTANA.

American Bar. The lowest bar on the Missouri River on which 

sapphires have been found. (See p. 47.)

CoUonwood Creek. In the.gravels of this creek greenish-colored 

sapphires have been found. (See p. 51. j

Dana Bar. A bar in the Missouri River, in the gravels of which 

sapphires have been found. (See p. 47.)

Eldorado Bar. Sapphires in the gravel. (See p. 47.)

Emerald Bar. The highest bar on the Missouri River in which 

sapphires have been found. (See p. 49.)

French Bar. Sapphires have been found in a small dike of andesite. (See p. 47.)

G-allaiin County. Corundum in syenite. (See p. 66.)

Magpie Gulch. Pale-greenish sapphires have been found in the 

gravel. (See p. 47.).

Metropolitan Bar. Sapphires occur in the gravels. (See p. 49.)

Missouri River bars. In the various bars along the Missouri River, 

18 miles east and northeast of Helena, sapphires'have been found in 

the gravel. (Seep. 47.)

Rook Creek. All colors of sapphires are found in the gravel of this 

creek. (See p. 50.)

Ruby Bar. Sapphires occur in an andesite dike. (See p. 47.)

Spokane Bar. A bar of the Missouri River where the most mining 

has been done for sapphires that occur in the gravels. (See p. 48.)

Yogo Q-ulcli. Blne, sapphires occur in a dike of minette. (See p.

52.)

NEVADA.

Silver Peak. Corundum lias been reported from near this place.

NEW JERSEY.

Franklin Furnace. A small pocket of corundum has been found 

here associated with dolomitic limestone.

Newton. Blue and white corundum occurs in a whitish feldspar 

near the contact of the granitic rock and white limestone.

Vernon. Small pockets of corundum in limestone, but not in great 

quantities. (See p. 36. N

NEW YORK.

Amity. Blue and white corundum has been found in the limestone 

near Amity and Warwick, Orange County. Does not occur in large 

quantity.
PBATT.] COKUNDUM LOCALITIES. 83

Peekskill. A short distance east of Peekskill emery is found in basic 

magnesian rocks in some quantity. (See p. 70.)

NORTH CAROLINA.

Acm& mine. This mine is located about three-quarters of a mile 

west of Statesville, Iredell County. The corundum occurs in crystals 

in an amphibolite.

Addie. Crystals of corundmn have been found sparingly associated 

with the peridotite rocks in the vicinity of Addie, Jackson County.

Bad Creelc mine. Corundum associated with peridotite. (See p. 

62.)

Bakersville. Corundum crystals have been found .sparingly in the 

gneiss at William Bowmans, three-fourths of a mile west of Bakersville, Mitchell County.

Belir mine. This mine is near Elf post-office, on Shooting Creek,

Clay County. Pink and white corundum, have been found associated 

with peridotite rocks.

Belts bridge. Crystals of black corundum occur in an amphibolite 

8 miles northwest of Statesville, Iredell County, on the Hunter farm.

Belts Gap. Corundum in splendid grayish-white crystals that are 

translucent are found in the gneiss to the south of the gap in, Jackson 

County. Garnet also occurs in the gneiss. 

Blue Ridge properties. Corundum occurs in gneiss. (See p. 59.)

Brockton mine. Corundum occurs in the peridotite. (See p. 61.)

Buck Creek mine. Also known as the Cullakeenee. Is in a peridotite formation. (See p. 58.)

Burnt Rock mine. In a peridotite formation. (See p. 61.)

Caler Fork. Ruby .mine, the crystals being found in the gravels of 

the creek. (See p. 40.)

Caney Fork. Two miles above the mouth of this creek, in Jackson 

County, corundum is found in the chlorite-schist in considerable 

quantity. At many points along this creek and its tributaries corundum has been found in the chlorite-schists and in gneiss near these 

schists, as at the mouth of and also 2 miles up Chastains Creek and 

on Shoal Creek Mountains on the West Fork.

Carpenters Knob. Along the ridge leading northwest from Carpenters Knob, near the border of Burke, Cleveland, and Catawba counties, corundum in grayish-blue tapering crystals is found associated 

with garnetiferous gneisses and schists.

Carter mine. Corundum occurs in a peridotite formation associated with spinel. Considerable work was done here ten years ago, 

but since then the mine has been idle. This locality offers a somewhat promising prospect.

Celos Ridge. Corundum ciystals 2 to 3 inches long have been found 

sparingly in the decomposed gneiss on this ridge 8 miles southeast of 

Burnsville, Yancey County.
84 CORUNDUM IN THE UNITED STATES. [nui,L. 180.

C'hastains Creek. See above, under Caney Fork.

Chunky Gal Mountains. Corundum has been found in the bands 

of quartz-schists and gneiss of which the Chunky Gal Mountains are 

composed. Garnet is associated with the corundum, which forms a 

very small percentage of the rock. This occurrence is described on 

page 34.

Collins mine. Pink corundum in cyanite occurs at this mine near 

Statesville, Iredell County.

Corundum Hill mine. The corundum at this mine occurs in a 

peridotite. (See p. 55.)

Cowee Valley.-^-Ruby and red corundum are found in the alluvial 

deposits of this valley, many of which are transparent. (See description of ruby mine, pp. 40-44.)

Coweeta. Pink corundum is found in a greenish cyanite at this, 

place, in Macon County.

Cullakeenee mine. Same as the Buck Creek mine.

Cullasagee mine. This is the same as the Corundum Hill mine.

Democrat Corundum has been found, sparingly associated with 

the peridotite rocks, a little to the south of this place, in Buncombe 

County.

Elf. Beautiful specimens of pink corundum are found in the green 

amphibolite. Occasionally there are blue pieces in this rock.

Egypt mine. This mine is located in Yancey County, 10 miles west 

of Burnsville, and the corundum is in a peridotite. It is in crystalline masses and distinct crystals of a white color, often mottled with 

blue. This occurrence is interesting as being the only one where 

corundum has been found surrounded directly by dunite.

Ellijay Creek. Corundum has been found at many points in the 

valley of this creek, associated with peridotite rocks. The more 

important of these are the Mincey, Haskett, and Higdon mines.

Fairview mine. At this mine emery occurs in basic magnesian 

rocks. (See p. 7.2.)

Fishhaiuk Mountain. At an elevation of 4,000 feet on the western 

slope of this mountain, on Hickory Knoll Creek, in Macon County, 

corundum has been found sparingly in a small outcrop of dunite.

Fostef mine. Near the summit of Chunky Gal Mountains, near the 

headwaters of the northern fork of Shooting Creek, in Clay County, 

corundum occurs in peridotite. (See p. 60.) f

Gaston County. Blue corundum, associated with mica and quartz, 

has been found at Chubbs, Chrowders, and Kings mountains in this 

county. Emery also has been found at Chrowders Mountain.

Glenville. Four miles north of this town, in Macon County, corundum occurs in chlorite-schist similar to that on Caney Fork.

Gray property. Corundum in peridotite. (See p. 58.)

Grimshaw Gem. mine. Sapphires of various colors have been found 

at this mine in peridotite. It is near Montvale post-office, Jackson 

County. (See p. 45.)
PHATT.] COKUNDUM LOCALITIES. 85

Hampton mine. Same as Mine Fork.

Haskett mine. This is given under E Hi jay Creek.

Herbert mine. This mine is on Little Buck Creek, Clay County, 

and is in a long, narrow arm of peridotite extending out from the 

main mass of the Buck Creek peridotite formation. Some prospecting 

has been done here, and although corundum has been found, the main 

mass of it occurs in connection with the main mass of peridotite.

Higdon mine. This mine'was worked for a short time, and there 

is connected with it a mill for washing and cleaning the ore. (See 

El 11 jay Creek, above.)

Isbel mine. Corundum occurs sparingly in what may be a decomposed amphibolite. One of the largest washing and cleaning mills in 

the State is at this mine.

Kings Mountain. See Gaston County.

Marshall. Corundum has been found in large gray crystals half 

mile north of the mouth of Big Ivy River and 3 miles above Marshall, 

Madison County, on the surface of a large amphibolite outcrop. It 

is on the property of G. C. Haynie, of Marshall. It has also been 

found on the property of Hon.. J. C. Pritchard near the same town.

Me Christians place. Emery of reddish-brown and grayish colors 

has been found at this place, which is 7 miles north of Friendship, 

Guilford County. The property lacks development. Surface specimens of corundum have also been found here.

Mincey mine. The corundum at this mine is found in peridotite. 

(Seep. 58.)

Mine Fork. Emery, associated with staurolite.

Montvale. At many of the peridotite formations in the Aric:mity of 

Montvale, Jackson County, corundum has been found. (See p. 45.)

Newfound Gap. A little to the south of this gap,, in Haywood 

County, red corundum has been found on the surface of a small mass 

of dunite.

Nona. Corundum in distinct crystals has been found on the surface, in the vicinity of gneiss, at Nona, Macon County.

Owens Creek. Crystals and grains of corundum have been found 

in bowlders of cyanite near the mouth of this creek, in Transylvania 

County. '

Presley mine. This mine is located 4 miles north of Canton, Haywood County. The corundum, of a blue and bluish-gray color, 

occurs in a pegmatitic dike.

Reed mine. The corundum at this mine, which is 6 miles east of 

Franklin, Macon County, occurs in a saprolitic rock, and is in small 

prismatic crystals of a bluish color, some of which are nearly transparent.

Retreat. Near Retreat post-office, in Haywood County, corundum 

has been found in limited quantity in small pegmatitic dikes in the 

ffneiss.
86 CORUNDUM IN THE UNITED STATES. . [BULL. 180.

Sapphire. The mines in the vicinity "of this town are described on 

page 61.

Sapphire 'rame. The corundum occurs in peridotite. (See p. 61.)

Scaly Mountain. The corundum occurs in quartz-schist. (See 

p. 60.)

Sheffield mine. The corundum at this mine is in amphibole-schist. 

(See p! 58.)

Slteener Crap. Emery is found here in a basic magnesian rock. (See 

P- 72.)

Shoups Ford. At this place, in Burke County, corundum has 

been found associated with fibrolite.

Socrates mine. One of the mines in the vicinity of Sapphire. 

Corundum, occurs in peridotite. (See p. 62.)

Swannanoa Gap. Float corundum has been found near an outcrop of peridotite.

Thumping Creelt. -^-Corundum has been found in rough nodules 

and flat crystals in gneiss on the property of Curtis Ledford and C. C. 

Patterson, on this creek, Macon County.

Turkey Knob. On the summit of this mountain, near the MaconJackson county line, corundum has been found sparingly in gneiss.

Waldroop mine. Emery has been found in a basic magnesian rock. 

(See p. 72.) . Watagua mine. Same as the Reed mine.

West Mitts. Red and ruby corundum have been found in the old 

gravel beds of the streams OIL the West farm, near West Mills, Macon 

County.

Whitewater mine. The corundum is in peridotite. (See p. 63.)

Winston Salem. Near this place, in Forsyth County, emery has 

been found similar to that at the McChristian place.

Yellow Mountain. The gneisses of this section cany a small percentage of corundum. (See p. 60.)

PENNSYLVANIA.

Blackhorse. Slender grayish crystals of corundum have been found 

at this place, which is near Media, Delaware County. This has been 

found inclosed by feldspar.

Fremont. Near this place, in West Nottingham Township, Chester 

County, corundum crystals have been found, surrounded by feldspar.

Mineral Hill. Corundum crystals have been found at this place, 

which is near Media, in Middletown Township, Delaware County, 

which Avere surrounded by feldspar similar to that at Blackhorse.

Newlin. See under Unionville.

Shimerville. At this place, in Lehigh County, corundum crystals 

up to 8 inches in length and 4£ inches in diameter have been found 

loose in the soil.. . Unionville. In a large mass of serpentine rocks, 1 mile northeast 

of this village, corundum has been found. (See p. 66.)
PHATT.] CORUNDUM LOCALITIES. 87

Viiiagegreen. Large crystals of corundum of a brownish color are 

found near this village, in Aston Township, Delaware County.

West Chester Corundum has been found in a serpentine of this 

township..

SOUTH CAROLINA.

Anderson County. Corundum has been reported from this county, 

but none has been found in place.

Energy. See York County.

G-affney. Corundum, usually of a gray color and in irregular masses 

up to 3 or 4 inches in diameter, has been found about 8 miles northwest of Gaffney, on the Island Ford road, near Maud post-office, on 

the Turner Phillips farm. It has not been found in situ, but in the 

gravels of a small stream and as loose fragments in the fields on the

adjoining slopes. The fragments and what few crystals have been

found are generally free from gangue, but some have been found 

with mica scales attached to them. It is not at all improbable that 

this corundum was derived from a mica-schist.

La/wrens. About 1£ miles northeast of this town, in Laureus 

County, corundum has been found rather abundantly scattered over 

the surface. This surface corundum has been found for a number of 

miles to the southwest of this town. Although no corundum has 

been found in place, it was probably derived from a mica-schist, for 

the country rock in this section is largely a schist, and corundum 

crystals were found with portions of the mica-schist attached to 

them. The crystals are all rough, and vary from small ones to some 

that were over 3 inches long and 1 inch in diameter.

Oconee County. Corundum has been found on the surface in this 

county, but none has been found in place.

York County. In the northern part of this county, at Energy, 

near the North Carolina line, a black corundum has been found quite 

abundantly. (Seep. 66.)

UTAH.

It is reported that a large deposit of corundum was found in this 

State during the past year, but no accurate information has been thus 

far obtained regarding location or quantity.

VIRGINIA.

Louisa County. Deep blue crystals of corundum have been found 

in the soil in this county, but the exact locality is not known.

Stuart. Corundum has been found in a mica-schist near this place 

on Bull Mountain. (See p. 35.) No development of the occurrence 

has been made to determine the extent of the deposit or the percentage of corundum.
88 . CORUNDUM IN THE UNITED STATES. [BULL. 180.

ALASKA. 1

Copper River. Asteriated corundum of gray and pink colors is said 

to occur in a locality on Copper River, Alaska.

CORUNDUM LOCALITIES IN FOREIGN COUNTRIES.

With the exception of the emery deposits of Turkey and the- Grecian Archipelago there were no localities outside of the United States 

where corundum had been mined for abrasive purposes until, during 

the last year or two, when work was begun at the India deposits. As 

preparations are being made to work both these and the Canadian 

deposits on a large scale, it has seemed to me that a short description of them would be of interest and of value. I have also added a 

short description of the emery deposits of Turkey and the Grecian 

Archipelago.

CANADA.

The Canadian corundum localities that are attracting considerable 

attention at the present time are in the Province of Ontario, and have 

been recently described by Prof. W. G. Miller, 2 of the Kingston School 

of Mines. The corundum occurs as a primary constituent of. a rock 

that is classified as a syenite and has been traced for over 50 miles 

across Renfrew, Hastings, and Haliburton counties, with smaller belts 

of the same rock in Peterborough, Lanark, and Frontenac counties to 

the south, making a total distance of nearly 100 miles in which the 

corundum-bearing rock has been found.

The rock varies from a normal syenite to a nepheline-syenite and a 

mica-syenite. Corundum has been found in all three of these varities, but is more abundant in the normal syenite, and this rock has 

been named corundum-syenite. These rocks, which occur as dikes

cutting through the gneisses, are sometimes in large masses that 

appear to grade into a granite. The width of the dikes varies greatly, 

but is usually several feet; a few have been observed that were only 

a few inches wide. These dikes are sometimes thickly studded with 

corundum crystals. Assays made of this rock from various parts of 

the dikes indicate that it will average about 12 per cent of corundum. 

If the corundum can be mined economically, and if tests of the commercial corundum obtained from the ore show that it has the abrasive 

qualities essential to make it of use in the manufacture of vitrified 

wheels, these deposits should become of considerable importance.

The Canada Corundum Company, Limited, has been organized and 

has begun mining operations on the corundum deposits in the extreme northwestern part of Raglan Township, Renfrew County, 

Ontario, about 7 miles southwest of Combermere. The corundum

i Twentieth Ann. Kept. U. S. Geol. Survey, Part VI, 1899, p. 570.

1 Report Bureau of Mines, Toronto, Can., Vol. VIII, Part IE, 1899, pp. 205-240.
PHATT.] CORUNDUM LOCALITIES. 89

liere occurs in the normal syenite. A corundum mill has been erected 

that will have a capacity of 5 tons of cleaned corundum a day.

This company also owns corundum deposits on the York Riverin Carlow and Dungannoii townships, Hastings County. At these 

localities the' corundum occurs in a nepheline-syenite, and while it is 

apparently of superior quality to that found in Raglan Township, the 

percentage of corundum is not as high. No mining is being done by 

the company at these York River localities.

The manager of the company is Mr. B. A. C. Craig, of Toronto, 

Canada.

Miller' has described specimens of corundum from Methuen Township, Peterborough County, that are entirely inclosed by mica. He 

says: "The corundum is often not observed in the mica until the 

latter is broken open, when, it is found forming the center or core of 

the mass. The rounded surfaces of the corundum and other characteristics leads to the belief that the masses of light-colored mica are 

secondary products after corundum." This very closely resembles 

specimens of corundum surrounded bj' muscovite mica that have been 

found at the Presley mine in Haywood County, N. C. (see p. 85), 

in which the muscovite is undoubtedly a secondary product after the 

corundum.

In the township of South Sherbrooke, Lanark County, 2 corundum 

has been found in a rock that is made up of a basic plagioclase feldspar 

and green hornblende, and has been called anorthosite by Miller. It 

is more basic in character than the typical varieties of this rock that 

have been described from other parts of Canada. The width of the 

belt of rock is nearly three-quarters of a mile and the corundum is 

found throughout the whole distance. It occurs in crystals of an 

almost uniform light-gray to white color that are usually about half 

an inch in diameter,'the largest ones being one and a quarter inches 

long.

INDIA.

The corundum deposits of India have been described by T. H. Holland. 3 He gives the Pararapatti area in the Salem district of the 

province of Upper Burma as one of the most promising for the mining 

of corundum for abrasive purposes. Pie describes the corundum as 

occuring in a matrix of deep flesh-colored feldspar which is in bands 

or lenticular masses, and has associated with it often a considerable 

proportion of sillimanite, rutile, opaque black and green spinel, and 

biotite. These masses, where they have been actually seen in the 

rock, are sometimes as much as 15 feet long and 8 feet in.diameter. 

The feldspar rock is composed essentially of anorthite and hornblende,

1 Report Bureau of M.ines, Toronto, Ontario, Vol. VIII, Part IT, 18911, p. 210. 

'^Loccit., p. 25.

3 Geology of India, Part III, Economic Geology, and Report Bureau of Mines, Vol. VIII, Part 

II, 189!), p. 3130.
90 CORUNDUM IN THE UNITED STATES. [BULL. 180.

and in parts has a gneissoid structure, and these portions carry the 

corundum. The corundum varies from a deep purplish brown to a 

dark greenish gray, and is in irregular nodules varying from a quarter 

of an inch to an inch in diameter and in elongated barrel-shaped crystals sometimes an inch long.

There are two and perhaps more of these corundum-bearing bands 

that are parallel to. each other, making the total length of corundumbearing rock that is known over 24 miles. The percentage of corundum in the rock is very low, experiments that have been made on 

samples taken at different points on the band showing the presence 

of only 3.5 per cent.

Most of the outcrops of the bands of corundum rock have been found 

in connection with gneiss, and lie in lines that are roughly parallel to 

the strike of the gneiss. Some of them are, however, in close proximity to a nepheline-syenite.

Specimens of corundum sent by Dr. T. L. Walker from a district 

about 250 miles north of Calcutta and labeled Pipra, South Rewah, 

India, are apparently similar to those described by Holland. The 

corundum is very fine grained in appearance and in nodules up to 

2 or more inches long by 1 or more inches broad, with a pinkish to 

purplish-brown color. These nodules are partially or completely surrounded by a greenish mica, whose folia are small and rather brittle, 

and which has been referred by Mallet 1 to the euphyllite variety. In 

the mica there are small rough crystals of tourmaline. Just what the 

occurrence of this corundum is I do not knoAv, but from the general 

appearance of the specimens it should make an ore from which the 

corundum could be readily separated and a very clean product 

obtained. If the corundum in the rock was 10 to 15 per cent of the 

amount required to be removed in mining, this should make a very 

important and profitable corundum deposit. A limited aulount of this 

corundum is now being imported by the Norton Emery Wheel Company, of Worcester, Mass., and is used in the manufacture of their 

India oilstones.

In other specimens labeled Salbanni, 4 miles east southeast of 

Barampur, Manbhoorn district, India, there are blue crystals of 

corundum with a rough hexagonal prism embedded in a mass of interlocking bladed crystals of cyanite.

It is very probable that nearly all of the corundum deposits that 

are known in India are secondary minerals and the result of metamorphism. Professor Judd, in his paper on the Rubies of Burma and 

associated Minerals, 2 says that all the corundum-bearing rocks in 

the districts of Southern Asia appear to be gneisses that sometimes 

pass into schists and frequently contain masses of limestone and 

dolomite.

1 Min. India, 1887, p. 130, and Daiia's Min., 6th edition, 1892, p. 624.

2 Trans. Royal Soc.,London, 1896, p. 191.
CORUNDUM LOCALITIES. 91 

TURKEY.

The Turkish, emery is obtained from the province or vilayet of 

Aidin, in Asia Minor, which embraces nearly the entire basins of the 

rivers Sarabat and Mender. Smyrna is .the principal town of the 

province, and is the center of trade for all the surrounding district 

and islands. The deposits that are now being worked are on the 

Guinush Dagh Mountain and on the slopes of Ak Sivri, 1 which is a 

mountain about 125 miles to the south. The former of these deposits 

is about 12 miles east of the ruins of Ephesus, and just north of the 

river Mender; the latter is in what J. Lawrence Smith 2 describes as 

the Kulah district, and it is much more inaccessible than the former 

one. Emery has also been found in small quantities near Adnla, a 

town about 12 or 15 miles east of Kulah, and also at Manser, about 24 

miles north, and at Allahinan-Bourgs, about 20 miles south of Smyrna.

The occurrence of the emery at all these localities is very similar, it

being embedded in a bluish, coarse-grained to compact marble or limestone, resting upon mica-slates, schists, and gneisses. It always occurs 

in the limestone or marble; not even a trace has as yet been found in 

the other rocks. It does not occur in a well-defined vein but in pockets 

scattered irregularly through the rock that are sometimes up to 200 

feet in length and 300 feet in width. The walls of these pockets are 

very irregular, as the limestone intrudes upon them, and then recedes 

very suddenly.

GRECIAN ARCHIPELAGO.

In a number of! the islands of this archipelago, emery has been 

found in considerable quantity. The most important of these localities is the island of Naxos, where the emery is found in large blocks 

more or less mixed with the red soil, and also embedded in white marble. 

The deposits are located principally on the north and east sides of the 

island, the best ore being obtained from Vothrie, which is 9 miles from 

the coast. Another one of the better deposits on this island is at 

Apperonthos, which is.7 miles from the coast. In the southern part 

of the island the emery is found near Yasso. It occurs in such 

abundance on the island, in loose bowlders and in the soil, that there 

has been little need to mine it in the hard rock.

On the island of Nicaria emery has been found in quality equal to 

that from Naxos, but the quantity is not so great. A little was also 

found on the island of Samos. In all these islands the emery occurs 

in a limestone.

OTHER LOCALITIES.

Corundum has been found sparingly at many other localities, but 

thus far it has not been found in quantity enough to make the occurrences of economic importance as an. abrasive.

1 Trans. Ain. Inst. Min. Eng., Vol. XXVIII, 1898, p.206.

2 Am. Jour. Sci., 2d series, Vol. X, 1850, p. 357.
92 CORUNDUM IN THE UNITED STATES. [BULL. 180.

The occurrence of sapphire corundum in Burma, Ceylon, and. Siam 

has been mentioned on pages 39 and 46. .

Zirkel, 1 mentions the occurrence of corundum as an accessory mineral in the amphibolites of northwestern Austrian Silesia; in the 

chlorite-schist of Nischne-Issetsk, in the Urals; as a contact product 

of the diorites of Klausen, in Tyrol; in the andesite and tonalite of 

the Eifel; in a contact product of quartz-mica-diorite on quartzphyllite in Val Moja, and similarly in the kersantite of Michaelstein, 

Harz; also in the graphite of Miihldorf, near Spitz, in Lower Austria.

Pirsson 2 has mentioned the occurrence of corundum in small blue 

sapphires in the fresh basalt of Unkel on the Rhine and Steinheim 

near Frankfort on the Main.

Morozewicz 3 has described the occurrences of corundum in Russia, 

the chief of which is in a rock composed essentially of anorthite and 

corundum, together with spinel and biotite. He claims that this is a 

new type of alumino-silicate rock, and calls it "kyschtymit." Other 

rocks in the Urals that contain corundum are made up almost exclusively of this mineral and orthoclase; some of these are coarse grained, 

while others are fine. The coarse ones have been called corundumpegmatite and the finer ones corundum-syenite. These rocks occur 

as dikes cutting through gneiss.

It may be that when these corundum-bearing rocks of the Urals 

have been more specially examined as to their economic value they 

may be found to contain a large enough percentage of corundum to 

make them of importance as an ore of this mineral.

Dana 4 mentions the occurrence of corundum near Canton, China; 

in Bohemia, near Petschau; at Saint Gotthard, in dolomite; near 

Mozzo, in Piedmont, in white compact feldspar; and at Mudgee, New 

South Wales.

Lacroix, in a paper 5 on the metamorphic and eruptive rocks of

Ariege, prance, mentions the occurrence of corundum in the marbles 

of Mercus and Arignac. In a second paper 6 on acid inclusions in the 

volcanic rocks of the Auvergne, France, corundum is said to occur 

frequently in the granites and gneisses of this section. He has also 

described the occurrence of this mineral in the basic magmas (basalts, 

trachytes, and andesites) in Haute-Loire, France. 7

Salomon8 has described the occurrence of corundum in phyllites, 

epidote-amphibolites, and mica-schists at Mount Aviolo, in the 

Southern Alps. It occurs but sparingly in these rocks.

1 Lehrbuch der Petrographie, Leipsic, 1893, p. 461. 

a Am. Jour. Sci.,4th series, Vol. IV, 1897, p. 422.

3 Tschermaks Min.und Pet. Mitt., Vol. XVIII, pt. 1; and Rept.Bureau of Mines, Toronto, Vol. 

VIII, Part II, 1899, p. 285.

4 Min., (ith edition, 1892, p. 212.

5 Bull.des Serv. d. 1. Carte geol. d. Prance, No. 11, Vol. II; and Am. Nat.,Feb., 1891,pp. 138-139. 

0 Loc. cit.

7 Bull. Soc. Min, Vol. XIII., 1890, pp. 100-100.

8 Jour. d. d. G. G-., Vol. XLII., 1890, p. 450; and Am. Nat., 1891, pp. 571,572.
PHATT.] CORUNDUM LOCALITIES. 93

In the dune sands on the west coast of Holland, at Sheveningen 

near the Hague, corundum has been found by Retgers 1 to be one of 

its constituents.

In describing the geology of the district around Pretoria, South 

Africa, Molengraaf a states that the oldest rocks of the region are 

granites and crystalline schists. Above these are another series of 

schist formations, comprising quartzites, clay slates, corundum 

schists, porphyroids, and chiastolite-schists that are cut by diabase 

dikes. He states that the corundum porphyroid resembles a feldspal' 

porphyry, and that the corundum occurs in large individuals in a 

groundmass of quart/!; and chlorite. From the description given, 

there is a possibility that there is corundum in quantity in this 

district.

In many parts of the western Ynrinan district, China, as in the 

prefecture of Shunning Fu, sapphire, ruby, and emerald corundum 

are said to occur. 3

1 Eec. des travaux chirniques cles Pays-Bas, Vol. XI, 1893, p. 109; and Am. Nat., 1893,p. 382. 

" Nenes Jahrbucli, Vol. IX, 1894-95,pp. 174-291; ami Am. Nat., 1895,p.470.

3 U. S. Consular Reports, Jan., 1900, Vol. LXII, No. 233, p. 95; reprinted from Mesuy's Chinese 

Miscellany, published at Shanghai, China.

INDEX.

Page. 

Acme mine,N.G.,corundum at.....-.- 83

Acworth,Ga.,corundum near ............ 80

Addie,N. C.,corundum at...-...-. .... 83

Africa,corundum in................... ---- 93

Alabama,corundum in... ................ 79

Alaska, corundum in ......... .......... 88

Alps, corundum in......................... 92

Aluminum, use of corundum in manufacture of........ ............. -.... --.-.-. 78-79

Airerican Bar, Mont., sapphires at....... 47,82

Amity. N. Y., corundum, at................ 82

Amphibole-schist,corundum in............ 31-33

Amphibolite, corundum in................ 21-26

emery in............................... 23-26

Auderson County, S. C., corundum in .... 87

Andesite,corundum in.................... 29-30

Bad Creek mine, N.C., corundum at... 63-63,83 

Bakersville.N.C.,corundum at.......:... 83

Bauer,M.,cited ............................ 43,54

Beavett mine,Ga.,corundum at.......... 81

Behr mine,-N.C., corundum at............ 83

Bell Creek mine, Ga., corundum at....... 80

Belts bridge, N.C., corundum at.......... 83

Bement, .S.,reference to ................ 39

Betts Gap,N.C.,corundum at............ 83

Biotite, corundum in ...................... 19-20

Bird,R.,reference to ...................... 49

Blackhorse,Pa.,corundum at............. 86

Blake, W. P., cited......................... 36

Blue, A.,cited.............................. 31

Bohemia, corundum in ._...-.............. 92

Brockton mine,N.C.,corundum at....... 61,83

Buck Creek, N. C., peridotite at, map

showing.............--....-.--..... 32

peridotite at,plate showing .......... 10

Buck Creek mine, N. C., corundum at. 58-59,83

view of................................. 60

Buckley, J.H.,reference to ............... 71

Bull Mountain, Va.,corundum at......... 35,87

Burnt Rock mine, N.C., corundum at.... 61,83

Byram, N. J., corundum in limestone 

near..................................._ 36

Caler Fork,N. C.,ruby-bearing gravel at,

plate showing................ ...... 40

rubies near ......................... 40-44,83

California,corundum in................... 79-80

Canada, corundum in....-;.--............. 88-89

Caney Fork,N.C.,corundum at .......... 21,83

Carpenters Knob, N. C., corundum at.... 83

Carter mine, N.C., corundum at......_. 15,83

Celos Ridge, N.C., corundum at.......... 83

Cement wheel,method of manufacture.. 78 

Centralhatchee, Ga., corundum at........ 80

Chaffee County,Colo.,corundum in...... 80

Page. 

Chandlers Hollow, Del., corundum at .... 80

Chase,D.,reference to .................... 71

Chemical wheel, method of manufacture. 77 

Chester, Mass., emery at.,....... 23-26,67-70,82

emery deposit at,map showing....... 08

Chlorito-schist,corundum in .............. 21

China, corundum in....................... 92,93

Chunky Gal Mountains, corundum at. 34.60,84 

Clay County, N. C., amphibolito and

corundum in....................... 21-22

Cleaning corundum,methods of......--.. 74-75

Colorado, corundum, in.................... 80

Collins mine, N.C., corundum at .. .' 84 

Connecticut,corundum in ................ 80

Copper River, Alaska, corundum on...... 88

Cortlaud Township, N. Y., emery in...... 70-71

Corundum,cleaning,methods of......... 74-75

distribution of......................... 37-73

hardness of ............................ 10

localities of ............................' 79-93

mining,methods of.................... 72-74

occurrence of....................... 10,1.1-37

theoretical composition of........ . 10-11

'uses of-.....-.-.-.....--..----.----.-.- 75-79

varieties of ............................ 9

Corundum Hill, dunito vein at, cross section of--.....--....--.------.-...-.. 14,15

peridotite at,map of ...=............... 56

peridotite formation at, plate showing ................................. 56

sapphires at ........................... 46-47

vein at, plate showing ................ 56

Corundum Hill mine, N. C., big cut at,

plate showing .......I............. 58

corundum at ....................... 55-57,84

corundum contact vein at, cross section of............................... 13

rubies at............................... 39-40

Cottonwood Creek, Mont., sapphires 011 51-52,

. 82 

Cowee Valley, N. C., corundum in..... 40-44,84

ruby crystals from, plate showing... 43 

ruby mine at,plate showing.......... 40

rubies in ............................... 4fl-44

Coweeta, N.C., corundum at............. 84

Craig.B. A.C., reference to............... 89

Crittenden, H., reference to.............. 49

Cullakeenee mine, N. C., corundum at.... 58-59

ruby corundum at.............___.____ 45

Cullasagee, N. C., corundum mill at, views

of................................... 74

sapphire at...............^.'........... 46

Cullasagee mine. See Corundum Hill 

mine.

95
96 INDEX.

Cyanite, corundum in...__-_..__-------...

Dalton, O., reference to...................

Dana,J.D.,cited........................ 27,

Dana Bar, Mont., sapphires at............ 47,82

Delaware,corundum in................... 80

Democrat, N.C., corundum at. .....--_..- 84

Diamond, hardness o£..................... 10

Dobson Mountain, N.C., emery at....... 72

Douglas County, Ga., corundum in....... .SO

Dudleyville, Ala., corundum near.... :.., 79

Dunite. See Pei-idotite..

Dunite vein,cross section of...---------- 14,15

open cut on, plate showing............ 58

Dunito veins,plates showing .......... 58,01),60

Durrant, J.,reference to .................. 49

Edman,J.A.,cited ........................ 80

Egypt mine, N.C., corundum at.-_.__._._ 15,84 

Eldorado Bay,Mont.,sapphires at ....... 47,82

Elf,N. C.,ruby corundum near........... 45

sapphires near......................... 47

Elf mine, N. C., corundum at....--.---.... 84

Ellijay Creek, N.C., corundum at ........ 84

Emerald Bar, Mont., sapphires at........ 49,82

Emerson,B.K.,cited...................... 23,24

quoted.......-.....-. ............... 19,20

Emery, distribution of.................... 67-72

in amphibolite....... ........ ...... 23-26

Energy, S. C.,corundum at............... 87

Enstatite, corundum in.................... 20

Evans, A.,information furnished by ..... 04

Fairview mine,N.C.,corundum at.. .... 72,84

emery at............................... 72

Pishhawk Mountain, N.C., corundum at. 84 

Poster mine,Ga.,corundum at.---. 00,65,80,84 

Prance, corundum in....................... 92

Franklin,N.C.,einery near.......'........ 72

rubies near ............................ 40-44

Franklin Furnace,.N.J.,corundum at.... 82

Premont,Pa.,corundum at......--------- 86

French Bar, Mont.,corundum at......... 29-30

sapphire at .............._ ... .... 47,82

Friendship, N.C.,emery near............. 72

Gaffney, S. C., corundum at............... 87

Gainesville.Ga., corundum near.......... 80

Gallatin County, Mont., corundum in.... 30-31,

66,82 

Garnet, hardness of ....................... 10

Gaston County, N. C., corundum in ...... 84

Genth,F.A.,cited ...................... 35,37,72

Georgia,corundum in............... 63-65,80-81

peridotite rocks and corundum, localities, map showing ................. 54

Glenville,N.C.,corundum at.............. 84

Gneiss, contact between peridotite and,

plate showing.-..--------- ...... 64

contact vein from peridotite to, cross

section of .......................... 12-14

corundum in........................... 33-34

cross section of peridotite after intrusion in......-. ...................... 16

vein between peridotite and, plate

showing...... -.-...-.. .......... 56

Grecian Archipelago, corundum in ...... 91

Grimshawe, C., reference to............... 45

Grirnshawe Gem Mine, N. C., corundum at 45,84 

Gross Ridge, N. C., corundum in gneiss at. 33-34 

Habersham County, Ga., corundum in ... 81

Hamilton mine, Ga., corundum at .. 

Hampton mine, N. C., corundum at. 

Hanover, Ala., corundum near......

Haskett mine, N. C., corundum at........

Haynie,C. C., reference to ................

Heady,H.,reference to....................

Herbert uiine.N. C.,corundum at.......- .

Hills, R. C., cited ...........................

Higdon mine, oST. C., corundum at _........

Hiwassee, Ga., corundum near.............

Hobson,S. S.,reference to...... ............

Hog Creek mine,Ga.,corundum at.......

Holland, T.H.,cited...... ..........". ......

Holland,corundum in.-_-..-...____. ......

Hunters,N.C., corundum at..............

Huntington,Mass.,emery at..............

In Situ Hill, N. C., rubies at ...............

India,corundum in.................. ......

Isbel mine,N.C-rcorundum at............

Johnson,C.,reference to..................

Judd,J.W., cited..........................

King,F.P., cited...........................

Kings Mountain, N. C. See Gaston

County. 

Knuth, W., acknowledgments to..........

reference to ...........................

Kuuz.G.F., cited ....................... 29;

Lacroix,A.,cited ..........................

Laurel Creek, Ga., duuite vein at, plate 

showing.............................

open cut at, plate showing............

peridotite formation at, map showing

peridotite formation at. plate showing 

Laurel Creek mine,Ga.,corundum at. 63 

Laurens, S. C., corundum at ..............

Lawson, A. C., cited................'.........

Le.dford,C.,reference to..................

Ledford, J., reference to ..................

Limestone,corundum in ..................

Litchflekl,Conn.,corundum near ........

Louisa County, Va., corundum in.........

Lucas, H. S., reference to..................

Macia mine, Mass., emery at..............

Magpie Gulch,Mont.,sapphires.at.......

Mann,W.,reference to....................

McCoy, Isaac, reference to .......-.....---

Marshall, N.C.,coru7idum near...........

Maryland, corundum in............. ...--.

Mason Branch, N.C., rubies near..........

Massachusetts, corundum in. .............

emery in.........'....-.--...-...---.-..

Melvin mine,Mass.,emery at.............

Metropolitan Bar, Mont., sapphires at....

Mica-schist,corundum in .................

Miller,W.G.,cited...................... 31

Mincey mine, N.C., corundum at.........

open cut at. plate showing ............

ruby corundum at.....................

Mine Fork,N. C.,corundum at.-----------

Mineral Hill,Pa.,corundum at...........

Minette, basic, corundum in ..............

Mining corundum,methods of ............

Missouri River bars, sapphire crystals 

from,figure showing..............

sapphires in ....'.-................. -

Moffltt, W.,reference to ...................

Molengraff,cited .................... ......

'age.. 

81 

85 

79

84

85

71 

85 

80 

85 

80 

55 

81 

89 

93 

23

70,82 

41

89-90 

85 

49 

90 

65

50

49,50

47,52

92

60 

64 

64 

66

-65,81 

87 

80 

86 

72 

36

36,80 

87 

72 

68

47,82

 72 

71 

85

81 

40-44

82 

67-70

68

49,82 

34-a5 

88,89

45

85

28-29

72-74

50

47, J

50

93
97

Page. 

Monroe.Ga., corundum near ............. 81

Montana,corundum in.........I....... 66-07,82

sapphire deposits in, map showing location of..-..............--.---.--- 46

sapphires in ................... ....... 47-55

Montvale, N. C., corundum near.......... 45,84

Morozewicz, cited......................... 92

Nannies Mountain, S. C., corundum at... 66 

Nevada, corundum in...... ............ 82

New Jersey, corundum in................ 82

New York, corundum in .................. 82-83

emery in................................ 70-71

Newfound Gap, N.C.,corundum at ...... 85

Newlin, Pa., corundum at................. 66,86

Newton, N.J., corundum at .............. 83

Nona,N.C.,corundum at ................. 85

Norite,corundum in ...................... 20-28

North Carolina,,corundum in....... 55-63,83-80

emery in............................... 72

peridotite rocks and corundum localities, map showing................. ;>i

sapphires in ........................... 46-4"

Norwich,Conn..corundum near.--.-..... SO

Oconee County, S.C., corundum'in ....... 87

Old mine,Mass.,cross section of.......... 0!)

Oriental ruby, distribution and character

of......... .................. .... 39-40

Oriental sapphires,occurrence of ........ 46

Owens Creek,N. C.,corundum at-.....-.. 85

Patterson,C.C.,reference to............... 80

Peekskill,N.Y.,corundum............. 20-28,83

emery near ............................ 70-71

 Pelham,Mass.,corundum at...... -..-.--. 19,83

saxonite at............................. 19

Pennsylvania,corundum in............ C6,8ti,87

Peridotite' at Corundum Hill,N. C., map

. of................................... 56

contact between gneiss and, plato

showing............................. '(it

corundum in........................... 11-19

cross section of, after intrusion in

gneiss............................. 10

outcrop of,plate showing..-..--...... 30

transition from corundum to, cross 

section showing ...................

vein between gneiss and, plate showing .................................

vein, contact from gneiss to, cross section of..............................

Peridotite formation at Corundum Hill,

N. C., plate showing ............... 50

Peridotite rocks in Georgia and North

Carolina, map showing location of 54 

Pine Mountain,Ga.,corundum ab ........ 81

Pirsson,L. V.,aid by....................... 30

cited ................................... 29,92

quoted........................... 28-29,32-33

Plumas County,Cal.,corundum in ....... 79-80

Porter Springs,Ga.,corundum at........ 81

Powder Springs,Ga., corundum at....... 81

.Presley mine, N. C., corundum at......... 85

Pritchard, J.C.,reference to.............. 85

Quinn.H.M., reference to.............._ 71

Rabuu Gap, Ga., corundum at ............ 81

Reed mine,N.C.,corundum at ........... 85

Bull. JSO 01 7

rage. 

Retgers, J. W., cited....................... 93

Retreat,N.C.,corundum at............... 85

Rock Creek, Mont., sapphires on....... 50-51,83

Ruby, oriental, distribution and character o*............................... 39-46

Ruby Bar,Mont.,sapphires at... ........ 47,82

corundum in andesite at.............. 29

Ruby-.bearing gravel at Caler Fork, N. C.,

plate showing ..................... 40

Ruby crystals,plate showing............. 43

Ruby mine ut Cowee Valley, N. C., plate

showing............................ 40

Sackett mine, Mf<ss., emery at............ 08-69

Salomon, W.,cited......................... 93

Sapphire, N. C., corundum near ....... 61 -63,86

peridotito areas in vicinity of, map of. 62

sapphires at ........................... 47

Sapphire crystals, figures showing....... 50

plate showing.......................... 52

Sapphire deposits in Montana, map showing location of..................... 46

Sapphire:*, distribution of................: 38-55

varieties of .......................... D-10,39

Sapphires, oriental, occurrence ot........ 40

Saxonite,corundum in contact with..... 19

Scaly Mountain,N.C.,corundum at...... 60,86

Serpentine,corundum in ................. 20

Sheffield mine, N. C., corundum at.. 31-33,58,86 

Shimerville,Pa.,corundum at............ 80

Shoups Ford, N. C., corundum at ......... 86

Silver Peak, Nov., corundum at.......... 82

Skeener Gap, N. C., emery at............. 72,86

Smith,J.L.,cited.......................... 47,91

Snow mine,Mass.,emery at .............. 09-70

Socrates mme,N.C.,corundum at ....... 62,86

South Carolina, corundum in............. 06,87

Sphalerite, hardness of.................... 38

Spokane Bar,Mont.,sapphire at....... 48-49,82

Spratt, A. N., reference to ................ 49

Spratt,F.,reference to........ ............ 49

Statesville, N. C., corundum in amphibolite at.............................. 22-23

Stone mine, Ga., corundum at............ 81

Stuart, Va.,corundum near......... ...... 35,87

Swannauoa Gap, N. C., corundum at... .a 80

Syenite, corundum in..................... 30-31

Teltonville, Ga., corundum, near ......... 81

Thomastou, Ga., corundum near .......... 81

Thumping Creek, N. C., corundum at. 33-3-1,80 

Towns County, Ga.,amphibolite and corundum in.......................... 21-22

Track Rock mine, Ga., corundum at..... 05,81

Traphagen, F. W., aid by................. 31

Turkey, corundum in..................... 91

Turkey Knob, N. C., corundum at........ 80

Uuionville, Pa., corundum at............. 06,86

Uses of corundum......................... 75-79

Utah, corundum in........................ 00,87

Vernon, N. J., corundum at.............. 36,82

Villagegreen, Pa , corundum at.......... 87

Virginia, corundum in ........;_.......... 87

Vitrified wheel, method of manufacture. 77 

Vogt, J. H. L., cited....................... 27

"Waldroop, J. A., inference to ............ 73

Waldroop mine, N. C., corundum at..... 72,86
98 INDEX.

Walker, T. L., reference to ...............

Watauga mine, 3ST. C., corundum at......

Webster, N. C., chlorite schist near......

peridotite at, relation of gneiss to. ...

Weed, W. H., cited...... ...... ............

Wells, G. A., reference to........... .. 

West Chester, Pa. , corundum at ....;.....

West Mills, N. C., corundum at ..........

West Point, Ga., corundum near.........'

Wheel, cement, method of manufacture. 

Wheel, chemical, method of manufacture 

Wheel, vitrified, method of manufacture

age.

90

85

21

12

Whitehall, Md., corundum in... ..-.. ...... 81

Whitewater mine, 1ST C., corundum at... 63,£6 

Williams, G. H., cited ..................... 26,27

Winston Salem, N. C., corundum at...... "86

Wrightmine, Mass., emery at............ 67-68

Yellow Mountain, N. C., corundum at ...-60,86 

Yogo Gulch, Mont., corundum in basic

nimette at......................... 28

sapphire crystals from, plate showing 52 

sapphires on........................ 52-55,82

Zeb Jones mine, N. C., corundum at ..... 57

Zirkel, F., cited ............................ 92

0