Tenacity
-
Very brittle
Solubility
-
insoluble
Durability
-
-
Specific Gravity
-99993.30-3.40
1
7.18
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Fracture
-
Conchoidal
Cleavage
-
{010} perfect, {110} distinct, {100} in traces
Mohs Hardness
-99996.5-7
2
10
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Chemical Composition
SiO2, Al2O3, CaO, MgO, FeO
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references