Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.90-2.983.355-3.433
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Uneven
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
{???} Good, {???} Good
Mohs Hardness
7.5-8-9999
2
10
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Chemical Composition
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)