Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.21-3.382.9-3.5
1
7.18
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Fracture
Irregular/uneven, Uneven
Conchoidal
Cleavage
Perfect on {001}
{110} Perfect, {???} Distinct, {???} Distinct
Mohs Hardness
6-75.5-6
2
10
👆🏻
Chemical Composition
Ca 2Al 3(SiO 4) 3(OH)Walter Schumann , Gemstones of the world (2001) More from other references
(Mg,Fe2+ ) 2(Mg,Fe2+ ) 5Si 8O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)