Black Sapphire
Form of corundum with a black/green hue due to Fe and titanium impurities.
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Appearance
Black sapphires are found in the form of star sapphires. These dark six-rayed stars are very attractive. These can be confused with star diopside which only have a four-rayed star.
This purplish - black sapphire from Burma is transformed into commercially usable pink sapphire after a flux additive is put in the heating process. Traditional heating of sapphires typically takes 2-3 days.
Also referred to as Bio Lemon Black Star Sapphire:A black sapphire formed from corundum with Titanium and Iron impurities.
cab star black sapphire, p. 59, 1p.
Fall 1970, A 12-rayed star sapphire, p. 231, 2pp.
Spring 1971, A fluorescent dye in treated corundum, p. 285, 1p.
Spring 1972, A 3-phase inclusion in a fine purple corundum, p. 11, 1p.
Pale transparent and dark opaque nearly black Sapphires are common in the marketplace at prices ranging from ten to two hundred dollars.
The "Mid night Star"- a black sapphire is also famous one. Both of these Star Sapphires are housed at the American Museum of Natural History in New York City. 330-carat "Star of Asia" at the Smithsonian is another famous Star Sapphire in the world..
Black Star Sapphire - A cabochon cut black sapphire with a 6 ray star. These stones are always heat treated to improve their color.
 See also: Sapphire, Color, Stone, Cut, Shape
  
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