Argentopentlandite

General Information:
 Chemical Formula:
Ag(Fe,Ni)8S8
 Composition:
(Molecular Weight = 816.86 gm)
Iron 41.02 % Fe
Nickel 14.37 % Ni
Silver 13.21 % Ag
Sulfur 31.40 % S 
 Empirical Formula:
AgFe2+6Ni2S8
 IMA Status:
Approved IMA 1977
Physical Properties:
 Cleavage:
[???] Good
 Color:
bronze brown.
 Diaphaniety:
Opaque
 Hardness:
3.5 - Copper Penny
 Luster:
Metallic
 Streak:
reddish brown
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