Geerite

General Information:
 Chemical Formula:
Cu8S5
 Composition:
(Molecular Weight = 668.70 gm)
Copper 76.02 % Cu
Sulfur 23.98 % S 
 Empirical Formula:
Cu8S5
 IMA Status:
Approved IMA 1978
Physical Properties:
 Color:
white or blue gray.
 Density:
5.61
 Diaphaniety:
Opaque
 Luster:
Metallic
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