Violarite

Violarite (Fe2+Ni23+S4) is a supergene sulfide mineral associated with the weathering and oxidation of primary pentlandite nickel sulfide ore minerals.Violarite crystallises in the isometric system, with a hardness of 4.5 to 5.5 and a specific gravity of about 4, is dark violet gray to copper-red, often with verdigris and patina from associated copper and arsenic sulfides, and is typically in amorphous to massive infill of lower saprolite ultramafic lithologies.
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n. violarite (Minerals)

General Information:
 Chemical Formula:
Fe++Ni+++2S4
 Composition:
(Molecular Weight = 301.49 gm)
Iron 18.52 % Fe
Nickel 38.93 % Ni
Sulfur 42.54 % S 
 Empirical Formula:
Fe2+Ni2S4
 Locality:
KEY W
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
violet gray, copper red, light gray, or steel gray.
 Density:
4.5 - 4.8, Average = 4.65
 Diaphaniety:
Opaque
 Hardness:
4.5-5.5
 Luminescence:
Non-fluorescent.
 Luster:
Metallic
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