Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
5.6-5.765.2
1
7.18
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Fracture
Uneven
Subconchoidal, Conchoidal
Cleavage
[001] perfect; [100] distinct
Good in one direction
Mohs Hardness
2.5-36-6.5
2
10
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Chemical Composition
Pb 5Cu 2(SO 4) 3(CO 3)(OH) 6Anthony et al , Handbook of mineralogy (2001)
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references