Tenacity
-
-
Solubility
-
Partly soluble in HCl.
Durability
-
-
Specific Gravity
3.26-3.363.32-3.43
1
7.18
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Fracture
Conchoidal
Conchoidal
Cleavage
Good on {100}
{100} perfect; {110} and {1 1 0} good; {010} poor
Mohs Hardness
6.5-75.5-6
2
10
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Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references