Tenacity
Brittle
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
2.90-2.985.6-5.76
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Uneven
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
[001] perfect; [100] distinct
Mohs Hardness
7.5-82.5-3
2
10
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Chemical Composition
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Pb 5Cu 2(SO 4) 3(CO 3)(OH) 6Anthony et al , Handbook of mineralogy (2001)