|
44
|
GEMS AND PRECIOUS STONES IN THE
|
||
|
|
|||
|
rence
of corundum' at the Culsagee and Laurel Creek localities, both of which
are now operated by the Hampden Emery Company, of Chester, Mass. The
Culsagee outcrop, covering some thirty acres, consists of chrysolite
(dunite) mingled with hornblende. The corundum is enclosed among
various hydromica-ceous minerals, commonly grouped, under the term
chlorite, between the gneiss and the dunite, from the alteration of
which they have evidently been formed. It occurs chiefly in crystalline
masses, often of considerable size, and sometimes suitable for gems. At
other parts of the mine it is found in small crystals and grains
mingled with scales of chlorite, forming what is called the " sand
vein." This is so loose and incoherent that it is worked by the
hydraulic process; and the small size of such corundum is the saving of
much labor in the next process of pulverizing. The Laurel Creek Mine is
similar in character. At Buck Creek the chrysolite rocks cover an area
of over 300 acres, and from that point southward the hornblende rocks
assume greater proportions, being associated with albite instead of
the ordinary feldspar and forming an albitic cyanite rock. There is
also found here the beautiful green smaragdite, called by Professor
Shepard chrome arfved-sonite, which, with red or pink corundum, forms a
beautiful and peculiar rock curiously resembling the eclogite or
omphacite of Hoff, in Bavaria, Germany. At Shorting Creek in Clay
County and in Towns County, Ga., there are also corundum localities.
The resemblance in the occurrence of the North Carolina corundums to
that of Mramorsk in the Ural Mountains, as described by Prof. Gustav
Rose of the University of Berlin, has been shown by Professor Genth.8
There the associated species are serpentine and chlorite schist,
sometimes with emery, dia-spore, and zoisite, very similar to the
chrome serpentine corundum belt of the Southern States. The emery
deposits of Asia Minor and the Grecian Archipelago, according to Dr. J.
Lawrence Smith,3 yield that substance in marble or
limestone, overlying gneissic rocks; while with it are associated many
of the same hydromicaceous and chloritic species that accompany both
the New England emery and the Southern corundum.
1 Mineral Resources of the United States, p. 714, 1883-1884.
* Contributions to the Laboratory of the University of Pennsylvania, No. I, 1873.
* Am. J. Sci. II., Vol. 10, p. 35s, Nov., 1850; and Vol. 12, p. 53, Jan., 1851.
|
|||
|
|
|||