Helmutwinklerite

General Information:
 Chemical Formula:
PbZn2(AsO4)2·2(H2O)
 Composition:
(Molecular Weight = 651.85 gm)
Zinc 20.06 % Zn
Arsenic 22.99 % As
Hydrogen 0.62 % H 
Lead 31.79 % Pb
Oxygen 24.54 % O 
 Empirical Formula:
PbZn2(AsO4)2·2(H2O)
 IMA Status:
Approved IMA 1980
Physical Properties:
 Cleavage:
None
 Color:
colorless or sky blue.
 Density:
5.3
 Hardness:
4.5 - Between Fluorite and Apatite
 Luster:
Vitreous - Resinous
 Streak:
white
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