Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.362.69-2.79
1
7.18
👆🏻
Fracture
Conchoidal
Conchoidal
Cleavage
Good on {100}
Poor on {0001}
Mohs Hardness
6.5-75.5-6.5
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
KNa 2(Fe3+ ,Mn3+ ,Al) 2Li 3Si 12O 30Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references