Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.365.5
1
7.18
👆🏻
Fracture
Conchoidal
Conchoidal
Cleavage
Good on {100}
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
6.5-75-5.5
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references