Tenacity
Brittle
-
Solubility
-
Partly soluble in HCl.
Durability
-
-
Specific Gravity
3.20-3.323.32-3.43
1
7.18
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Fracture
Uneven, Conchoidal
Conchoidal
Cleavage
Poor
{100} perfect; {110} and {1 1 0} good; {010} poor
Mohs Hardness
6-6.55.5-6
2
10
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Chemical Composition
(Mg,Fe2+ ) 7(SiO 4) 3(F,OH) 2Anthony et al , Handbook of mineralogy (2001)
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references