Tenacity
Very brittle
-
Solubility
insoluble
-
Durability
-
-
Specific Gravity
3.30-3.40-9999
1
7.18
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Fracture
Conchoidal
-
Cleavage
{010} perfect, {110} distinct, {100} in traces
-
Mohs Hardness
6.5-7-9999
2
10
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Chemical Composition
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references
SiO2, Al2O3, CaO, MgO, FeO