Alloclasite

Alloclasite ((Co,Fe)AsS) is a mineral found in Romania.
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General Information:
 Chemical Formula:
(Co,Fe)AsS
 Composition:
(Molecular Weight = 165.15 gm)
Iron 8.45 % Fe
Cobalt 26.76 % Co
Arsenic 45.37 % As
Sulfur 19.42 % S 
 Empirical Formula:
Co0.75Fe2+0.25AsS
Physical Properties:
 Cleavage:
[101] Perfect, [010] Distinct
 Color:
steel gray.
 Density:
6.17
 Diaphaniety:
Opaque
 Hardness:
5 - Apatite
 Luster:
Metallic
 Streak:
black
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