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PRECIOUS STONES.
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157
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central
Alps provide the largest crystals, some from the Tiefen Glacier, found
in 1868, measuring nearly 26 inches in length ; one of the best of the
specimens is now in the Museum at Berne ; altogether some 15 tons of
crystals were found in this one cave. One specimen in the national
collection in the British Museum is over 3 feet long. Other localities
are Mursinka in the Urals, where also Amethyst is found ; and with
Amethyst and other precious stones in the gravels in Ceylon. North
American localities include Paradise River, in Nova Scotia ; Pike's
Peak in Colorado; Magnet Cove, Arkansas; Goschen, Massachussets.
It
is usually step-cut, sometimes brilliant-cut. In ScotÂland it is
largely used in the mounting of Highland dress accoutrements.
Its
specific gravity alone is sufficient to distinguish it from other gem
stones of the same colour. In addition its hardness and faint dichroism
would distinguish it from any glass imitation.
7.
Milky Quartz is a crystalline variety, showing, as its name
implies, a milky colour. It is not important in the present relation.
8.
Sapphire Quartz, or Siderite, also known as Azure Quartz, is a
blue variety, showing a finely fibrous enclosure ; it is rarely cut as
a gem stone ; it is found in an impure limestone at Golling, in
Salzburg.
9.
Sagenitic Quartz is a crystalline variety, containing enclosures
of minerals in fine needles. The forms met with in use as gems are also
known as Needle Stone, Venus' Hair Stone, and Flèches d'Amour. The
substance enclosed may be Rutile or Gôthite in the Avenus' Hair Stone ;
coarser acidular crystals of Rutile are seen in the Needle Stone,
Fibres of
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