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CAT'S EYE.
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153
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It consists of a quartz, mixed with parallel fibres of asbestos and amianthus.
Asbestos
and amianthus are two varieties of mag-nesian silicates ; the first,
rigid in its fibres ; the other soft and somewhat elastic, having a
bright silken light and very fine fibres, easily separated and rather
pliant.
The
ancients used asbestos to make lamp wicks fed with petroleum, and being
incombustible it obtained the name which is derived from the Greek α-σβέννμι, (not to consume), incombustible.
They
wove the amianthus into a cloth, in which were wrapped the dead bodies
they wished to reduce to ashes, because the amianthus being
incombustible retained and preserved the ashes of the burned body.
Besides, this material, becoming purified by the action of the fire and
remaining in, it separated from every organic element, did not, in the
operation, take any blemish, whence its name of amianto, from the Greek a, privative, and μιαίνω, to stain.
The
cat's eye is found in pebbles and in pieces more or less round ; it has
a concave breakage ; is translucent and also transparent at the edges.
It has a vitreous and resinous light. It is generally either green,
red, yellow, or grey. It marks glass. Its specific gravity is from
2-560 to 2-730. When exposed to a great heat, it loses lustre and
transparency, but does not melt under the blow-pipe unless reduced to
minute fragments.
On analysis it gives
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