Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.363.95-4.10
1
7.18
👆🏻
Fracture
Conchoidal
Uneven
Cleavage
Good on {100}
{110} Perfect, {110} Perfect, {110} Perfect
Mohs Hardness
6.5-73.5-4
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
(Zn,Fe)SMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references