Tenacity
Brittle
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
2.90-2.984.1-4.3
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Uneven
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
Indistinct on {011}
Mohs Hardness
7.5-83.5-4
2
10
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Chemical Composition
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CuFeS 2Anthony et al , Handbook of mineralogy (2001)