Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.363.05-3.08
1
7.18
👆🏻
Fracture
Conchoidal
Subconchoidal, Uneven, Conchoidal
Cleavage
Good on {100}
Poor on {100}
Mohs Hardness
6.5-75
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Mn2+ Al(PO 4)(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)