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GEMS.
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namon or camellina, on account of its colour, which resembles that of oil of cinnamon. Werner was the first to call it essonite.
The
cleavage of the essonite is concave, but somewhat unequal ; it has
single refraction ; is transparent and translucent ; its light is
vitreous and resinous.
It is found of a dark red, or jacinth red, or orange-yellow colour.
It scratches glass and quartz, and is scratched by the topaz.
Its specific gravity varies from 3-5 to 3-6.
It
becomes electric by friction, and sometimes acts on the magnetic
needle. Under the action of the blow-pipe it melts easily into a light
green glass ; borax and acids have no effect on it.
The essonite is found in the sand of the rivers and in the primitive rocks of Ceylon and Scotland.
It
is distinguished from the gorgonzio by its superior hardness, specific
gravity, and brightness, and also the absence of double refraction. The
garnet is heavier, and the idocrasium lighter than the essonite, which
they both very much resemble.
XXXIX.
EUCLASIO.
Ax aluminous silicate which crystallizes in prisms, having four oblique faces, with longitudinal lines.
This substance, in repeated analyses, never gives the same result ; whence it is not possible to place it with
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