Tenacity
-
Brittle
Solubility
-
insoluble in water
Durability
-
-
Specific Gravity
2.60-3.025.00-5.20
1
7.18
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Fracture
-
Uneven, Conchoidal, ConchoidalWalter Schumann
Cleavage
Perfect
Indistinct on {001}; partings on {011} and {111}
Mohs Hardness
-99996-6.5
2
10
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Chemical Composition
(Mg,Fe2+ ) 5Al(Si 3Al)O 10(OH) 8Anthony et al , Handbook of mineralogy (2001)
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references