Tenacity
Brittle
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
2.51-2.532.90-2.98
1
7.18
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Fracture
Conchoidal, Splintery
Conchoidal, ConchoidalWalter Schumann
Cleavage
None
Distinct on {11 2 0}, imperfect on {10 1 1}
Mohs Hardness
57.5-8
2
10
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Chemical Composition
KNa 2B 3Si 12O 30Michael OâDonoghue , Gems, Sixth Edition (2006)
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references