Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.355-3.4333.87-4.14
1
7.18
👆🏻
Fracture
Uneven
Subconchoidal, Conchoidal
Cleavage
{???} Good, {???} Good
Poor on {120}, in traces on {001}
Mohs Hardness
-99995.5-6
2
10
👆🏻
Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references