Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.69-3.812.69-2.79
1
7.18
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Fracture
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
Conchoidal
Cleavage
Distinct on {110}, imperfect on {010}, poor on {001}
Poor on {0001}
Mohs Hardness
8.55.5-6.5
2
10
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Chemical Composition
BeAl 2 O 4
KNa 2(Fe3+ ,Mn3+ ,Al) 2Li 3Si 12O 30Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references