Tenacity
Brittle
Brittle
Solubility
-
Gelatinises in acids
Durability
-
-
Specific Gravity
5.00-5.302.4-2.5
1
7.18
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Fracture
Uneven, ConchoidalWalter Schumann, Conchoidal
Uneven, Conchoidal
Cleavage
None, may show partings on {0001} and {10 1 1}
Distinct on {110}
Mohs Hardness
65-6
2
10
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Chemical Composition
Fe 2O 3Arthur Thomas , Gemstones (2009)
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2