Tenacity
Brittle
Brittle
Solubility
Soluble
insoluble
Durability
-
-
Specific Gravity
2.756.86-7.03
1
7.18
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Fracture
Uneven, Conchoidal
Subconchoidal, Uneven, Conchoidal, Irregular
Cleavage
Imperfect on {110}
{100} imperfect, {110} indistinct; partings on {111} or {011}
Mohs Hardness
5.56-7
2
10
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Chemical Composition
(Na,Ca) 8Al 6Si 6O 24(SO 4,S,Cl) 2Ulrich Henn and Claudio C.
SnO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references