Cuprous sulfide, an ore of copper, usually occurring as black, fine-grained masses.
- ‘Numerous fissure veins and fracture planes were present that contained brittle arsenical copper and chalcocite.’
- ‘Cuprite occurred along with chalcocite as inclusions in small calcite crystals.’
- ‘Some specimen labels state that this coating is chalcocite, but, to the best of my knowledge, the identity has not been established by analysis.’
- ‘At the Kingston mine, calcite occurred as thin massive veins cutting the lode and as modified rhombohedral crystals to 7 mm with inclusions of cuprite and chalcocite.’
- ‘We have seen sooty black material associated with native copper from the Eagle mine that is almost certainly chalcocite.’