Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.363.03-3.18
1
7.18
👆🏻
Fracture
Conchoidal
Uneven, Irregular, Conchoidal
Cleavage
Good on {100}
{???} Indistinct
Mohs Hardness
6.5-77-7.5
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)