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A POPULAR TREATISE ON GEMS.
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In
graphic granite, associated with black tourmaline, good clear crystals
are found in Bocodoniham, and Tapham, Georgetown, Parker's Island, and
at the mouth of Kene-bec river, in the State of Maine ; at Goshen and
Chesterfield, Mass., in irregular crystals of a pale-green color ; and
transparent, at Monroe, in Conn., in a granite vein ; in Haddam, Conn.,
at the chrysoberyl locality, where the beryls of yellow and
yellowish-green colors are imbedded with crystals of chrysoberyl and
columbite.
ZIRCON, HYACINTH, JARGON.
'
Zircon and hyacinth were regarded as distinct minerals until the
improvement in chemical analysis proved the same constituents to exist
in both, particularly zirconia, a peculiar earth: they are now
considered.as two varieties of one and the same mineral. Zircon is also
called jargon, and this name is either of Ceylonese or French origin.
The ancients denominated hyacinth, the gem which is now known by the
name of carbuncle ; their true hyacinth was a dark amethyst. The zircon
was formerly used as a celebrated medicine.
Zircon
crystallizes in four-sided prisms, terminated by four-sided pyramids,
with various modifications ;* the crystals are smooth, rough, or
uneven; it occurs likewise in rounded pebbles; it is transparent and
translucent ; possesses double refraction in a great degree ; and has
a vivid vitreous lustre, approaching sometimes to adamantine. Color,
from hyacinth-red to yellow and brown ; also, red, gray, white, brown,
and greenish-gray. It slightly scratches
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