Crystal Grey Aventurine

Chemical Formula	SiO2
Color	Blue, Green, Yellow, Orange, Brown, Gray
Hardness	6.5 - 7
Crystal System	Hexagonal
Refractive Index	1.54 - 1.55
SG	2.63 - 2.65
Transparency	Opaque. May be translucent when backlit on the edges.
Double Refraction	.009
Luster	Vitreous, waxy
Cleavage	Indiscernible
Mineral Class	Quartz / Chalcedony