Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.76-3.775.2
1
7.18
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Fracture
-
Subconchoidal, Conchoidal
Cleavage
{110} Perfect, {110} Perfect
Good in one direction
Mohs Hardness
5-66-6.5
2
10
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Chemical Composition
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references