Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.43-3.444.76-5.03
1
7.18
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Fracture
-
Conchoidal
Cleavage
None Observed
None
Mohs Hardness
6.5-75.5-6.5
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
(Mn2+ ,Fe2+ ,Mg)(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)