Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.26-3.362.72-2.75
1
7.18
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Fracture
Conchoidal
Uneven
Cleavage
Good on {100}
Perfect on [001], good on [010], imperfect on [110]
Mohs Hardness
6.5-76-6.5
2
10
👆🏻
Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Ca(70-90%)Na(30-10%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)