Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.355-3.4335.5
1
7.18
👆🏻
Fracture
Uneven
Conchoidal
Cleavage
{???} Good, {???} Good
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
-99995-5.5
2
10
👆🏻
Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references