Tenacity
Brittle
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.20-3.323.90-4.00
1
7.18
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Fracture
Uneven, Conchoidal
Conchoidal
Cleavage
Poor
Perfect on {001}, good on {210}, poor on {010}
Mohs Hardness
6-6.53-3.5
2
10
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Chemical Composition
(Mg,Fe2+ ) 7(SiO 4) 3(F,OH) 2Anthony et al , Handbook of mineralogy (2001)
SrSO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references