CHRYSOLITE
The straw-yellow
to greenish-yellow variety only is known commercially as chrysolite. In
olive-green it is called peridot. The yellowish green variety, which is
the mineralogist's olivine, is also known commercially as peridot. It
is found in Egypt, Brazil, Mexico, Germany, Ceylon, South Africa, the
United States, and in meteorites.
Crystallization trimetric; form, rhombic prism; usually found as water-worn pebbles.
Hardness, 6.5 to 7; specific gravity, 3.3 to 3.5; heavy according to the proportion of iron and consequent dark color.
Lustre vitreous to greasy; transparent to translucent; electric by friction.
Cleavage
perfect, parallel to the smaller lateral plane; fracture conchoidal. It
looks like glass except in the direction of the cleavage.
Doubly refractive (index, 1.70 and 1.66) ; dichroic; twin colors of olive, brown-yellow and sea-green.
Composition varies: silica, 40; magnesia, 50; ferrous oxide, 9; nickel oxide, etc., I.
Excepting
those containing much iron, it darkens but does not fuse under the
blow-pipe, but fuses with borax to green glass and is attacked by
sulphuric acid.
Color, yellow and various shades of olive-green.
Cut step and brilliant; does not hold sharp, fine edges to the facets.
Symbolizes gladsome heart; September, on the Jewish list of month stones.
