Xonotlite

Xonotlite is a mineral with the chemical formula Ca6Si6O17(OH)2. It crystallizes in the monoclinic - prismatic crystal system with typically an acicular crystal form or habit. It can be colorless, gray, light gray, lemon white, or pink. It is transparent with a vitreous to silky luster. It leaves a white streak. Xonotlite is rated 6.5 on the Mohs Scale of hardness. It was first described in 1866 and named for its occurrence in Tetela de Xonotla, Puebla, Mexico It occurs as veins in serpentinite and contact metamorphism aureoles.
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General Information:
 Chemical Formula:
Ca6Si6O17(OH)2
 Composition:
(Molecular Weight = 714.99 gm)
Calcium 33.63 % Ca
Silicon 23.57 % Si
Hydrogen 0.28 % H 
Oxygen 42.52 % O 
 Empirical Formula:
Ca6Si6O17(OH)2
 Locality:
Santa Ynez, Santa Barbara Co., Califonia, USA.
Physical Properties:
 Cleavage:
[???] Good
 Color:
colorless, gray, lemon white, light gray, or pink.
 Density:
2.7
 Diaphaniety:
Transparent
 Habits:
Acicular - Occurs as needle-like crystals., Massive - Uniformly indistinguishable crystals forming large masses.,
 Hardness:
6.5 - Pyrite
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous - Silky
 Streak:
white
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XONOTLITE