Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.362.79-2.87
1
7.18
👆🏻
Fracture
Conchoidal
Conchoidal
Cleavage
Good on {100}
{010} perfect; {100} good, interrupted; {101} indistinct; {001} in traces
Mohs Hardness
6.5-75.5-6
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
NaBePO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references