Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.43-3.445.00-5.30
1
7.18
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Fracture
-
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
None Observed
None, may show partings on {0001} and {10 1 1}
Mohs Hardness
6.5-76
2
10
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Chemical Composition
Ca 2(Mg,Al) 6(Si,Al,B) 6O 20Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Fe 2O 3Arthur Thomas , Gemstones (2009)