Tenacity
Brittle
Brittle
Solubility
Soluble
-
Durability
-
-
Specific Gravity
3.30-3.506.5-7.1
1
7.18
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Fracture
Uneven, ConchoidalWalter Schumann, Conchoidal
Uneven, Conchoidal
Cleavage
Perfect on {110}, poor on {101}, {001} rare
Imperfect- [10 1 1]
Mohs Hardness
53.5-4
2
10
👆🏻
Chemical Composition
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)