Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.69-3.812.55-2.63
1
7.18
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Fracture
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
Uneven
Cleavage
Distinct on {110}, imperfect on {010}, poor on {001}
{001} Perfect, {010} Good
Mohs Hardness
8.56-6.5
2
10
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Chemical Composition
BeAl 2 O 4
KAlSi 3O 8Arthur Thomas , Gemstones (2009)