Tenacity
-
Slightly sectile
Solubility
-
1.04 x 10−25 g per 100 ml water (Ksp at 25°C = 2 x 10−32)
Durability
-
-
Specific Gravity
3.355-3.4332
1
7.18
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Fracture
Uneven
Uneven
Cleavage
{???} Good, {???} Good
Prismatic {10 1 0}, perfect
Mohs Hardness
-99992-2.5
2
10
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Chemical Composition
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)
HgSMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references