Tenacity
-
Brittle
Solubility
-
insoluble in water
Durability
-
-
Specific Gravity
3.26-3.365.00-5.20
1
7.18
👆🏻
Fracture
Conchoidal
Uneven, Conchoidal, ConchoidalWalter Schumann
Cleavage
Good on {100}
Indistinct on {001}; partings on {011} and {111}
Mohs Hardness
6.5-76-6.5
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references