table,
and when set requires a foil, colored by carmine or solution of gold,
as it fades when exposed a long time to the light. The rose quartz is
not held in great estimation ; the color as well as the lustre of faded
rose quartz may be resuscitated by being left for some time in a moist
place.
A vase of rose quartz was in the possession of the Marquis de Dree, nine inches high and two inches in diameter.
Cat's-eye.
The
name of this mineral is derived from the peculiar play of light
perceptible on its surface, by which it resembles the rays of light in
the eyes of a cat; it is not ascertained whether the ancients knew
this mineral, and whether it was comprised in their .asterias; but it
is well known that cat's-eye is in high estimation among the Malabars
and Moors; and it is worn throughout the whole East, where it is
employed as an amulet, being believed to possess the virtue of
enriching the wearer.
Cat's-eye
occurs massive, and in more or less roundish pieces; has a conchoidal
fracture ; is translucent and transparent sometimes on one end; it has
a shining lustre, between vitreous and resinous; gray and brown, green,
red and yellow color; it presents a peculiar floating light, which is
particularly visible if cut in high cabochon, as it usually is when
brought to market; it scratches glass; has a specific gravity of 2.56
to 2.73, and contains 95 silex, 1.75 alumina, 1.50 lime, and 0.26 oxide
of iron. In many specimens, fhere may be observed small parallel white
fibres, which are supposed to be the cause of its peculiar play of
light; but the semi-transparent varieties, which are equally chatoyant
as the more opaque ones, present no such appearance. This leads to the
conclusion that
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