Tungsten: A
metal of grayish-white color, of considerable luster, that is nearly as
hard as steel. When heated to redness in the open air, it takes fire
and is converted into tungstic acid. It is important in the manufacture
of the tungsten lamp and because of the refractory nature of this
metal, these lamps may be maintained at a high temperature and at an
expenditure of only about 1.25 watts per candle power. "Tungsten steel"
is a name given to steel containing a small amount of tungsten, and is
dis-tinquished for its hardness and tenacity, even under heat, (see
Wolframite) .
"Turkey-Fat Ore": A local name given to Smithsonite, in Arkansas, when it is colored bright orange-yellow by Greenockite.
Turgite:
A common Iron ore. Oxygen 28.5%, Iron 66.2%. This mineral is often
taken for Limonite, which it resembles except in superior hardness and
streak. Color reddish-black to dark red; bright red when earthy. It
occurs abundantly in large botryoidal masses, at the limonite ore bed
at Salisbury, Connecticut.
Turquoise: Hydrous Phosphate of Aluminium colored by copper.
It occurs massive, amorphous or crypto-crystalline;
reniform,
stalactitic or encrusting; in disseminated grains or in rolled masses.
This is the only opaque gem material which approaches the rank of a
precious stone.
The
most sought after color is a clear, intense sky-blue, but
comparatively few stones come up to this standard, the color ranging
from robins egg-blue to apple-green.
Nearly
all of the gem material comes from Persia and Turkestan, though of
late years it has been discovered in New Mexico, Nevada, Arizona and
Colorado. The name is French meaning "Turkish," the original stones
having come into Europe from Turkey.
A
favorite method of using Turquoise is in the matrix, small pieces of
the rock with inclusions of turquoise, being polished and sold as
Turquoise Matrix.
Tyrolite: Arsenate
of Copper. Arsenic Pentoxide 29%, Cupric Oxide 50%. Occurs in distinct
crystals, usually in fan-shaped forms; also reniform and massive. Color
pale
apple-green inclining to sky-blue.
This mineral occurs in the Tyrol, in Saxony, Siberia and Hungary; also at the Mammoth Mine in Utah.
