Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.76-3.772.97-3.03
1
7.18
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Fracture
-
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
{110} Perfect, {110} Perfect
{001} Poor
Mohs Hardness
5-67
2
10
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Chemical Composition
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
CaB 2(SiO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references