Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.90-2.985.5
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Conchoidal
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
7.5-85-5.5
2
10
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Chemical Composition
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references