Crystal Blue Sapphire

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