Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.33-2.372.69-2.79
1
7.18
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Fracture
ConchoidalWalter Schumann
Conchoidal
Cleavage
Perfect on {010}, good on {100}
Poor on {0001}
Mohs Hardness
7.55.5-6.5
2
10
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Chemical Composition
Be 2BO 3(OH)Ulrich Henn and Claudio C.
KNa 2(Fe3+ ,Mn3+ ,Al) 2Li 3Si 12O 30Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references