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GARNET, ZIRCON, RUTILE, AND OCTAHEDRITE. 51
possesses
a remarkable degree of brilliancy, especially in artificial light.
Those qualities give it great value for gem purposes, and it has become
very popular. The pieces found are not generally large, but stones have
been cut of as much as 14 carats. A very fine exhibit of rhodolites was
made in the State Geological Survey Exhibit at the recent Expositions
at Buffalo, Charleston, and St. Louis. They have been developed by two
companies with remarkable success; and apparently more gems in value
have been sold from this mine than from all other sources in the State
combined. (See PI. XIII.)
Perhaps $53,000 worth of these stones have been sold from these mines to date.
ZIRCON.
Zircon (silicate
of zirconia) is a mineral of somewhat wide distribution, though rarely
conspicuous. It crystallizes in square prisms with pyramidal
terminations, generally opaque and of some shade of brown. When
transparent, and of any size, beautiful gems can be cut from zircon
crystals; these are the hyacinths of jewelers.
In
North Carolina zircon is abundant in the gold sands of Polk, Burke,
McDowell, Rutherford, and Caldwell counties, and in nearly all the
colors found in Ceylon—yellowish-brown, brownish-white, amethystine,
pink, and blue. The crystals are beautifully modified, but too minute
to be of value. Brown and brownish-yellow crystals, very perfect in
form, occur abundantly in Henderson County, N. C, and in equal
abundance in Anderson County, S. C. The latter are readily
distinguished from the North Carolina crystals, as they are generally
larger, often an inch across, and the prism is almost always very
small, the crystal frequently being made up of the two pyramids only.
They are found in large quantities, loose in the soil, as the result of
the decomposition of a feldspathic rock. Large and richly colored
zircons, sometimes as much as 2 ounces in weight, and of fine shades of
brown and honey-red, are found in Iredell County.5.
Within
the past 20 years some demand has arisen and continued for minerals
containing the rare earths,—zirconia, thoria, etc.,—as these substances
are used for the mantles or hoods of the Welsbach and other forms of
incandescent gas burners. This demand led to active search throughout
the world for the minerals containing these oxides, and so successful
has been this search that many species which were once considered rare
are now so plentiful that they are quoted at one-tenth to one-
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