Tenacity
Brittle
Brittle
Solubility
Soluble
Dilute acid
Durability
-
-
Specific Gravity
3.10-3.202.93-2.96
1
7.18
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Fracture
Uneven, Conchoidal
Subconchoidal, Conchoidal
Cleavage
Poor to good on (001)
Distinct on {010}, imperfect {110} and {011}
Mohs Hardness
6-6.53.5-4
2
10
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Chemical Composition
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references