Tenacity
Brittle
Brittle
Solubility
Soluble
Soluble
Durability
-
-
Specific Gravity
3.10-3.203.25-3.35
1
7.18
👆🏻
Fracture
Uneven, Conchoidal
Conchoidal, ConchoidalWalter Schumann
Cleavage
Poor to good on (001)
Perfect in three directions
Mohs Hardness
6-6.55
2
10
👆🏻
Chemical Composition
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references