Chemical Formula
Al2O3
Color
White, Colorless, Blue, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Multicolored
Hardness
9
Crystal System
Hexagonal
Refractive Index
1.76 - 1.77
SG
3.9 - 4.1
Transparency
Transparent to opaque
Double Refraction
.0008
Luster
Vitreous to adamantine
Cleavage
None, but may exhibit parting
Mineral Class
Corundum
Certified Yellow Sapphire ...
Yellow Sapphire Loose Gems...
Cyelon Yellow Sapphire Loo...
Rare Yellow Sapphire Rough...