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	ChalcociteCu2S
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		| Class: SulfideHardness: 2.5 - 3
 Density: 5.5 - 5.8
 Streak: Blackish lead-gray
 Lustre: Dull metallic
 Habit: Chunky fracture, massive habit.
 Colours: Blackish lead-gray
 |  | Crystal System: Monoclinic Cleavage: Indistinct
 Fracture: Conchoidal
 Magnetism: None
 Reaction with HCl: None
 |  Identification in hand sample:Black colour with sooty appearance on weathered surfaces and sectile character are distinctive.  Bronze-yellow on fresh surfaces.
 Associations:Found in the supergene-enriched zone of copper-bearing hydrothermal sulfide deposits.
 Industrial / ecomonic uses:Mined as a source of copper.
 Comments:A substantial amount of material identified as chalcocite may actually be djurleite (Cu31S16), as they are very commonly intergrown.
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