Tenacity
-
Brittle
Solubility
-
insoluble in water
Durability
-
-
Specific Gravity
3.03-3.185.00-5.20
1
7.18
👆🏻
Fracture
Uneven, Irregular, Conchoidal
Uneven, Conchoidal, ConchoidalWalter Schumann
Cleavage
{???} Indistinct
Indistinct on {001}; partings on {011} and {111}
Mohs Hardness
7-7.56-6.5
2
10
👆🏻
Chemical Composition
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references