Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.413.85-3.94
1
7.18
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Fracture
Fibrous, ConchoidalWalter Schumann
Conchoidal, Uneven
Cleavage
Distinct on {100}, poor on {110}; parting on {001}
{010} Good, {100} Distinct
Mohs Hardness
7-8.55-5.5
2
10
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Chemical Composition
AlAl6O3BSi3O18
(Mn2+ ,Fe2+ ,Mg,Ca) 2(PO 4)(F,OH)Michael OâDonoghue , Gems, Sixth Edition (2006)