Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.7-3.84.76-5.03
1
7.18
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Fracture
Subconchoidal, Conchoidal
Conchoidal
Cleavage
Distinct on {010}
None
Mohs Hardness
7-7.55.5-6.5
2
10
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Chemical Composition
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
(Mn2+ ,Fe2+ ,Mg)(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)