Tenacity
Brittle
Brittle
Solubility
-
insoluble in water
Durability
-
-
Specific Gravity
1.795.00-5.20
1
7.18
👆🏻
Fracture
Irregular/uneven
Uneven, Conchoidal, ConchoidalWalter Schumann
Cleavage
Perfect on {10bar10}
Indistinct on {001}; partings on {011} and {111}
Mohs Hardness
2.56-6.5
2
10
👆🏻
Chemical Composition
Ca6(Al,Si)2(SO4)2B(OH)4(OH,O)12•26(H2O)
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references