Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.362.90-2.98
1
7.18
👆🏻
Fracture
Conchoidal
Conchoidal, ConchoidalWalter Schumann
Cleavage
Good on {100}
Distinct on {11 2 0}, imperfect on {10 1 1}
Mohs Hardness
6.5-77.5-8
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references