Yarrowite

General Information:
 Chemical Formula:
Cu9S8
 Composition:
(Molecular Weight = 828.44 gm)
Copper 69.03 % Cu
Sulfur 30.97 % S 
 Empirical Formula:
Cu9S8
 IMA Status:
Approved IMA 1978
 Locality:
Yarrow Creek, AB, Canada.
 Name Origin:
Named for the locality.
Physical Properties:
 Cleavage:
[0001] Distinct
 Color:
black or blue.
 Density:
4.89
 Diaphaniety:
Opaque
 Habits:
Tarnishes - Freshly fractured surfaces form a surface oxidation film, Massive - Uniformly indistinguishable crystals forming large masses.,
 Hardness:
3.5 - Copper Penny
 Luster:
Metallic
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