Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.97-3.035.05-5.22
1
7.18
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Fracture
Uneven, ConchoidalWalter Schumann, Conchoidal
Uneven
Cleavage
{001} Poor
None
Mohs Hardness
75.5-6
2
10
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Chemical Composition
CaB 2(SiO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Zn,Mn2+ ,Fe2+ )(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)