Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.76-3.772.9-3.5
1
7.18
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Fracture
-
Conchoidal
Cleavage
{110} Perfect, {110} Perfect
{110} Perfect, {???} Distinct, {???} Distinct
Mohs Hardness
5-65.5-6
2
10
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Chemical Composition
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
(Mg,Fe2+ ) 2(Mg,Fe2+ ) 5Si 8O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)