Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.90-2.982.97-3.14
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Uneven, Conchoidal
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
{1011} Indistinct
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(Mg 3)MgAl 5(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)