Tenacity
Brittle
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
5.00-5.302.75
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}
Imperfect on {110}
Mohs Hardness
65.5
2
10
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Chemical Composition
Fe 2O 3Arthur Thomas , Gemstones (2009)
(Na,Ca) 8Al 6Si 6O 24(SO 4,S,Cl) 2Ulrich Henn and Claudio C.