Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.69-3.812.50-2.80
1
7.18
👆🏻
Fracture
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
-
Cleavage
Distinct on {110}, imperfect on {010}, poor on {001}
Perfect
Mohs Hardness
8.55-6.5
2
10
👆🏻
Chemical Composition
BeAl 2 O 4
Na 4(Al,Si) 12O 24Cl to Ca 4(Si,Al) 12O 24(CO 3,SO 4)Arthur Thomas , Gemstones (2009)