Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.355-3.4333.1-3.2
1
7.18
👆🏻
Fracture
Uneven
-
Cleavage
{???} Good, {???} Good
Vitreous, pearly on cleavage
Mohs Hardness
-99993-4
2
10
👆🏻
Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
(Fe2+ ,Mg,Mn2+ ) 3(PO 4) 2 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references