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garnets,
tourmalines, etc. The zircons are in the form of rolled pebbles, rarely
of large size, few stones of over ten or twelve carats weight being
found. In other localities some noble zircons are found in panning for
gold, the high specific gravity of the zircon causing it to stay in the
pans almost as long as the gold. Along the Espailly River, in Auvergne,
France, are found zircons which yield brilliant though small stones of
the true jacinth color. Neither in the form of hyacinth, or jargoon, is
zircon at the present time very extensively used in jewelry, although
it has many of the qualities desirable for gems. The best stones are
rarely valued now at more than ten dollars per carat, although they
were once highly prized. One peculiarity of zircon
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been
found that the mineral when heated away from oxygen does not lose or
change its color, the conclusion is drawn by some that the color
depends on the state of oxidation of contained iron; but others think
it of organic origin. The red varieties of zircon are sometimes sold
for rubies, but they may be easily distinguished from true rubies by
their lower hardness and higher specific gravity. Zircon becomes
phosphorescent but not electric upon heating.
The
ancients employed a stone which they knew as hyacinth; but its color
was bluish, and hence it is generally supposed to have been our
sapphire or amethyst. The lyncurion of Theophrastus is more
likely to have been our zircon, the ancients having employed it for
making signets, some of which are still preserved. In the Middle Ages
hyacinth was supposed to have the power of procuring sleep, riches,
honor, and wisdom, and of driving away plagues and evil spirits.
Cardanus, writing in the sixteenth century, says that he was accustomed
to carry a hyacinth (jacinth) about with him for the purpose of
inducing sleep, which " it did seem somewhat to confer, but not much."
no
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