Tenacity
Brittle
-
Solubility
Gelatinises in acids
-
Durability
-
-
Specific Gravity
2.4-2.55.5
1
7.18
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Fracture
Uneven, Conchoidal
Conchoidal
Cleavage
Distinct on {110}
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
5-65-5.5
2
10
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Chemical Composition
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references