Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.76-3.775.5
1
7.18
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Fracture
-
Conchoidal
Cleavage
{110} Perfect, {110} Perfect
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
5-65-5.5
2
10
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Chemical Composition
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references