80 CORUNDUM IN THE UNITED STATES. [bujul. 180. 
composed of 8-4 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, supersat- 
urated 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 Calu- 
met iron mines in the mica-schists at their contact with intrusive dikes 
of diorite. R. 0. Hills, geologist to the Colorado Fuel and Iron Com- 
pany, writes that the ore occurs in a band of rock 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 spar- 
ingly 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 Con- 
cord, 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 Paulding 
County. From a pit sunk within this formation about 1,000 pounds 
of corundum were taken out. It is of poor quality, but makes hand- 
some mineral specimens. 
Bell Creek mine. — This mine is -f miles north of Hiwassee, Towns 
County, and the corundum, mostly of a pink color, occurs in a peri- 
dotite. 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, which 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 twine. — The corundum occurs in quartz-schist. (See p. (50.) 
Gainesville — Beautiful specimens of red corundum have been found 
in the peridotite formation 1 mile east of Gainesville, Hall County. 
1 A. C. Lawson: Am Geologist, Vol. XXVII, 1901, p. 132; J. A. Edruan, letters f rum. 
