Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.7-3.83.2-3.4
1
7.18
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Fracture
Subconchoidal, Conchoidal
Uneven
Cleavage
Distinct on {010}
Perfect on [001] imperfect on [100]
Mohs Hardness
7-7.53
2
10
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Chemical Composition
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
(K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)