SAPPHIRE
From the Greek sappheiros, name
of a blue gem. It is the name given to all but the red corundums,
being, color excepted, identical with the ruby. It is found in Siam,
Bur-mah, Ceylon, Cashmere, United States, and Australia.
Crystallization
hexagonal, occurring in double si#c-sided pyramids, found usually as
rolled pieces detached and separated from the original matrix.
Hardness, 9; specific gravity, 4, or nearly so.
Lustre vitreous; transparent to translucent.
Cleavage basal, breaking across the prism.
Double
refraction (index, 1.77 and 1.76) ; dichroic; twin colors of blue
sapphire, light greenish yellow and blue. Natural stones are often
dichroitic, blue one way, red the other.
Composition: pure alumina.
Infusible alone, but with borax melts to clear glass; unaffected by chemicals.
Color: gem color, corn-flower blue; occurs in all shades of blue, yellow, pink, green, etc.
It is cut step and en cabochon. Many small stones, especially Montanas, are now being cut brilliant.
The imperfections of cut stones consist of muddiness, clouds, spots, fissures, and white streaks.
Symbolizes constancy, truth, virtue, September, Andrew.
In star sapphire, or asteria, the summits of the primitive rhomboid are replaced by secondary planes. Cut en cabochon, with the summit over the point corresponding with the summit of the rhomboid, a star of six rays is produced, as in star ruby.
