Tenacity
-
Brittle
Solubility
-
insoluble
Durability
-
-
Specific Gravity
3.355-3.4336.86-7.03
1
7.18
👆🏻
Fracture
Uneven
Subconchoidal, Uneven, Conchoidal, Irregular
Cleavage
{???} Good, {???} Good
{100} imperfect, {110} indistinct; partings on {111} or {011}
Mohs Hardness
-99996-7
2
10
👆🏻
Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
SnO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references