Tenacity
Brittle
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
2.97-3.035.00-5.30
1
7.18
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Fracture
Uneven, ConchoidalWalter Schumann, Conchoidal
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
{001} Poor
None, may show partings on {0001} and {10 1 1}
Mohs Hardness
76
2
10
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Chemical Composition
CaB 2(SiO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Fe 2O 3Arthur Thomas , Gemstones (2009)