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AVENTURINE.
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43
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" Which some people call garamantite. It
is found in India, in a place of the same name, and also in Arabia. The
greatest beauty consists in the drops of gold, which always sparkle
inside, but never on the surface. Some people esteem the Arabic more
than the Indian stones." * There are two qualities of aventurine
quartz, of which the most common, which has marks of yellow mica, or
Muscovy talc, is found on the shores of the White Sea, in some mines of
Silesia, of Bohemia, France, and Siberia ; the other, more rare, has
bright reflections from minute chinks, and is found in Spain and
Scotland.
Its
specific weight is from 2·6 ; it slightly scratches rock crystal ; has
a bright light, does not acquire electricity from heat, and has no
power over the magnetic needle. The ground colour is generally
russet-brown, but there are some of yellow, grey, reddish-white, and
green with black and white marks. However, aventurine quartz has two
different aspects, viz., semi-transparent and opaque : the first has
the exact specific weight of 2-6670, the second 2*6426.
The
great demand for aventurine quartz, when it was fashionable,,
originated the idea of making the stone artificially. I do not believe
that chance could, by an accident happening to a workman, make such a
fine combination; therefore, with many modern authors, I claim the
glory for Miozzi, who, in the infancy of modern glass work, after long
study, was the first to make an aventurine glass, which, excepting in
hard-* Nat. Hist, xxxvii. vii. 28.
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