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894
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MINERAL RESOURCES, 1916----PART II.
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North
Carolina, and Pennsylvania. The pegmatite veins of the gneiss of
Manhattan Island, New York City, has yielded some very large garnet
crystals, two of which weigh 10 pounds 8 ounces and 9 pounds 10 ounces,
respectively. Such material, however, is of little gem- value. In
October, 1916, in the Washington Heights section of New York City, in
the block bounded by Haven and Northern avenues and West One hundred
seventy-eight and West One hundred seventy-ninth streets, James G.
Manchester found an incomplete crystal, about 3 inches in diameter, of
fine gem quality. A qualitative chemical examination demonstrated that
the material was the aluminum-manganese, species, spessartite, only
very small amounts of iron, calcium, or magnesium being present.
Although the New York material is similar to the spessartites of Amelia
Court House, Va., Manchester and Stanton1 describe it
as " more brilliant, more perfect, more translucent and of a more
beautiful color, being a clear, slightly orange-red, rather than the
cloudy brownish red." The material cut into 39 brilliant and step-cut
stones, of a combined weight of about 19 carats. The largest stone
weighed 1.37 carats.
QUARTZ.
The
varieties of quartz produced in 191G include agate, agate jasper,
agatized wood, amethyst, bloodstone, carnelian, common chalcedony,
citrine, blue and green chrysoprase, jasper, jaspcrized wood, moss
agate, rock crystal, rose quartz, smoky quartz, gold quartz, milky
quartz, rainbow quartz, touchstone, and quartz with inclusions of
dumortierite, hornblende, or rutile.
Mr.
Shelley W. Denton, Wellesley, Mass., reports finding near his home pale
lavender-colored quartz crystals (amethyst) loose and imbedded in a
fine mud which filled cavities in veins of quartz. Many gems of this
material were cut and sold under the name lavendine.
A new variety of rose-colored quartz from Nevada, suitable for cutting into gem stones, is described under dumortierite.
The itemized production of quartz gems is shown below:
Value of quartz gems produced in 1912-1916.
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