Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
2.50-2.802.33-2.37
1
7.18
👆🏻
Fracture
-
ConchoidalWalter Schumann
Cleavage
Perfect
Perfect on {010}, good on {100}
Mohs Hardness
5-6.57.5
2
10
👆🏻
Chemical Composition
Na 4(Al,Si) 12O 24Cl to Ca 4(Si,Al) 12O 24(CO 3,SO 4)Arthur Thomas , Gemstones (2009)
Be 2BO 3(OH)Ulrich Henn and Claudio C.