Tenacity
Brittle
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
6.5-7.13.30-3.50
1
7.18
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Fracture
Uneven, Conchoidal
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
Imperfect- [10 1 1]
Perfect on {110}, poor on {101}, {001} rare
Mohs Hardness
3.5-45
2
10
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Chemical Composition
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references