Tenacity
-
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
3.26-3.413.25-3.35
1
7.18
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Fracture
Fibrous, ConchoidalWalter Schumann
Conchoidal, ConchoidalWalter Schumann
Cleavage
Distinct on {100}, poor on {110}; parting on {001}
Perfect in three directions
Mohs Hardness
7-8.55
2
10
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Chemical Composition
AlAl6O3BSi3O18
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references