Tenacity
Brittle
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
3.69-3.813.25-3.35
1
7.18
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Fracture
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
Conchoidal, ConchoidalWalter Schumann
Cleavage
Distinct on {110}, imperfect on {010}, poor on {001}
Perfect in three directions
Mohs Hardness
8.55
2
10
👆🏻
Chemical Composition
BeAl 2 O 4
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references