Kyanite

Kyanite is more of a collector gem then a mainstream gem, and has not been extensively mined for gem use. Gem quality Kyanite has traditionally come from Brazil, Cambodia, and Burma, but these stones are generally not colored consistently . They usually have a grayish tone, and are not fully transparent, thus limiting their use as a gemstones. However, recent finds in Nepal of high quality Kyanite have been delivering gemstones of exceptional blue color and transparency, rivaling Sapphire.

Chemical Formula	Al2SiO5
Color	Blue
Hardness	4.5Â -Â 7
Crystal System	Triclinic
Refractive Index	1.71Â -Â 1.73
SG	3.5Â -Â 3.7
Transparency	Transparent to translucent
Double Refraction	-0.015
Luster	Vitreous
Cleavage	1,1;2,1
Mineral Class	Kyanite