Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.3-3.55.5
1
7.18
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Fracture
Uneven
Conchoidal
Cleavage
Perfect on [110]
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
5-65-5.5
2
10
👆🏻
Chemical Composition
NaNa2(Fe++4Fe+++)Si8O22(OH)2
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references