Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.355-3.4332.33-2.37
1
7.18
👆🏻
Fracture
Uneven
ConchoidalWalter Schumann
Cleavage
{???} Good, {???} Good
Perfect on {010}, good on {100}
Mohs Hardness
-99997.5
2
10
👆🏻
Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
Be 2BO 3(OH)Ulrich Henn and Claudio C.