AQUAMARINE
So called from its resemblance to sea-water.
It is a beryl, of which the emerald is the most valuable variety. Found in South America, Indies, Russia, and United States.
Crystallization
hexagonal, occurring in six- or twelve-sided prisms, usually long and
stout, without regular terminations and sometimes deeply striated.
Hardness, 7.5 to 8. Siberian aquamarine is said to be slightly harder than the emerald. Specific gravity, 2.65 to
2-75-
Lustre vitreous; very brilliant by artificial light; transparent to subtranslucent.
Cleavage in four directions; perfect only parallel to basal planes and indistinct. Fracture conchoidal, uneven.
Double
refraction (index, 1.582 and 1.576); dichroic; twin colors, light straw
and azure-blue, varying, with the depth and character of color, to
yellowish green and light bright blue; electric by friction, positive.
Composition varies: silica, 68; alumina, 15 to 20; glu-cina, 11 to 14.
Becomes
clouded before blow-pipe and fuses on edges with difficulty; melts with
borax to clear glass; soluble in salts of phosphorus, but is not
attacked by acids.
Gem color is a deep water-blue; general color, various shades of sea-green to colorless.
The finer qualities are now brilliant-cut in the United States.
Symbolizes happiness, everlasting youth; in Polish and Jewish lists, October.
Golden beryl is the same stone, in various shades of golden yellow.
