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842
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MINERAL RESOURCES.
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Specular
hematite occurs in minute flakes 1 or 2 millimeters in diameter in the
cavities and attached to rough topaz crystals. A few spessartite
garnets occur in the cavities with the topaz at this locality, and 3 or
4 miles to the west numerous garnet specimens were found in fair-sized
crystals. Bixbyite was found adhering to rough topaz crystals.
Though
topaz crystals are present over a large area, they are abundant over a
limited area only, probably half a mile across. The weathering of the
topaz-bearing rhyolite has left topaz crystals scattered abundantly
over the surface. These crystals are mostly very small and brilliant
though a few large transparent crystals have been found. The tiny
crystals shine brilliantly in the sunlight, making it difficult to
locate larger crystals by their reflections.
The
transparent topaz crystals, when of sufficient size for cutting, make
very brilliant gems, though perfectly colorless. They are sold under
the name of "white topaz," and are an attractive souvenir for tourists.
The crystals are also highly prized for collection purposes on account
of their transparency and the quality of the crystal faces. A. N.
Ailing" has described the following forms: Pinacoids, b (010), c (001);
prisms, m (110), 1 (120); macrodome, d (201); brachydomes, f (021), y
(041); pyramids, i (223), u (111), o (221), e (441).
TEXAS.
P.
H. and R. L. Parker, of Streeter, Mason County, report a production of
about 25 pounds of topaz crystals, some of which are of gem quality.
This topaz occurs in pockets, partly filled with clay, in a pegmatite
"vein" cutting a gneiss formation. Topaz is found at other localities
in this region, and a new discovery was made by the Parker brothers 12
miles north of Streeter. At the new locality topaz in good crystals is
reported to occur with blue feldspar.
SOUTH AMERICA.
Brazil.—A. S. Atkinson6
reports that old topaz mines of Boa Vista and Seramenhain in the basin
of Arassuahy Kiver have been reopened successfully by deep mining
methods after the open-cut work had been abandoned. Work is successful
at the Jose Correa and Coxambee mines also. The gems occur in a gravel
bed at a depth of about 20 feet. The topazes are valued for the
beautiful light to dark-yellow and deep-rose shades displayed by them,
combined with perfect transparency. A specimen in the Museum at Rio
Janeiro obtained from Jequitinhanha River at Ouro Preto weighs nearly
2,000 grams. It has a beautiful color, and is perfectly transparent and
absolutely flawless.
TOURMALINE.
MAINE.
The following notes on tourmaline and other gem minerals in Maine have been prepared from an article by W. R. Wade.c
The
gem-bearing area of Maine is about 70 miles long and 15 miles wide,
extending from Auburn to Newry. The principal gems are tour-
a Topaz from the Thomas Range, Utah: Am. Jour. Sci., 3d ser., vol. 33,1887, p. 146.
6 Mining for gems in Brazil: Eng. and Min. Jour., June 19,1909.
e Gem-bearing pegmatites of western Maine: Eng. and Min. Jour., June 5,1909.
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