696 MINERAL RESOURCES.
single
crystals, and the specimens of deep pink tourmaline in the pale lilac
mica are remarkably elegant. About 18 tons were mined during 1892. No
work has been done since then,
Tourmalines
are mined at the California gem mine, the San Jacinto gem mine, and the
Columbian gem mine, near Riverside, California. These three mining
claims cover the ground on which the tourmaline is found, and are
situated in the San Jacinto range of mountains in Riverside township,
California, at an altitude of 6,500 feet, overlooking Hemet •Valley and
the Cohuilla valley, and are 27 niiles from the railroad. The formation
in which the crystals are found is a vein from 40 to 50 feet wide
running almost north and south through the old crystalline rocks which
make up the mountain range.
The
vein in some places consists of pure feldspar, or else feldspar with
quartz, in others all mica, and in others rose quartz and smoky quartz.
The tourmalines vary in size from almost micrograms to crystals 4
inches in diameter. They are most plentiful in feldspar, but are found
in other portions of the vein, sometimes in pockets and sometimes
isolated. The larger crystals generally have a green exterior and are
red or pink in the center. Some of the crystals contain green, red,
pink, black, and intermediate colors: others again are all of uniform
tint— red, pink, colorless, or blue.
Associated
with the tourmalnies are rose quartz, smoky quartz, aste-riated quartz,
and fluorite, and some of the quartz was penetrated with fine,
hair-like crystals of tourmaline, strikingly like a similar occurrence
of rutile. One of the finest specimens found is now in the Harvard
College collection at Cambridge, Massachusetts. Another is in the
American Museum of Natural History, New York City.
A fuller description is contained in "The Bullion," El Paso, Texas, pp. 3-4, February 13,1894.
BERYL, EMERALD, AQUAMARINE.
No work was done at the emerald and hiddenite mine in Alexander county, North Carolina, during 1893.
According
to the last report of the British minister at Bogota, the celebrated
emerald mines of Muzo are situated about 80 miles to the north and
northwest of Bogota, on the banks of the river Minero. They are
Government property, but are farmed out to a Columbian-French syndicate
at a yearly rental of $11,250 (£2,250). The working expenses can be
roughly estimated at $50,000 (£10,000) per annum, and the mines yield a
fair profit, the production of emeralds being of the value of about
$100,000 (£20,000) annually. The rough stones are mostly sent to Paris
to be cut, as native work is inferior to foreign. These mines are
situated in a very rough, wild country, with nearly impassable roads;
at the present time there are about 300 natives employed there. The
mode of working is by open cuts, the debris being washed down the river
by water collected in a reservoir built above the level of the mine.
