Tenacity
Brittle
-
Solubility
Gelatinises in acids
insoluble
Durability
-
-
Specific Gravity
2.4-2.52.36
1
7.18
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Fracture
Uneven, Conchoidal
Uneven, Subconchoidal, Fibrous
Cleavage
Distinct on {110}
[110] perfect, [101] good, [010] distinct
Mohs Hardness
5-63.5-4
2
10
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Chemical Composition
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
Al 3(PO 4) 2(OH,F) 3 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references