Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.33-2.372.58-2.74
1
7.18
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Fracture
ConchoidalWalter Schumann
ConchoidalWalter Schumann, Splintery
Cleavage
Perfect on {010}, good on {100}
{100} Distinct, {110} Distinct
Mohs Hardness
7.55.5-6
2
10
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Chemical Composition
Be 2BO 3(OH)Ulrich Henn and Claudio C.
Na 4Al 3Si 9O 24Cl to Ca 4Al 6Si 6O 24(CO 3,SO 4)Walter Schumann , Gemstones of the world (2001) More from other references