Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.21-3.383.19-3.56
1
7.18
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Fracture
Irregular/uneven, Uneven
Uneven, Conchoidal
Cleavage
Perfect on {001}
{110} Perfect, {010} Indistinct
Mohs Hardness
6-75.5-6
2
10
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Chemical Composition
Ca 2Al 3(SiO 4) 3(OH)Walter Schumann , Gemstones of the world (2001) More from other references
(Ca,Na)(Mg,Fe,Al,Ti)(Si,Al) 2O 6Anthony et al , Handbook of mineralogy (2001)