Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.33-2.376.30-6.39
1
7.18
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Fracture
Uneven
Conchoidal
Cleavage
Perfect on {001}, imperfect on {110}
[001] good, [210] distinct
Mohs Hardness
4.5-53-3.5
2
10
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Chemical Composition
(K,Na)Ca4Si8O20(F,OH)•8(H2O)
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references