Pyrite, sphalerite and chalcopyrite. Cofer deposit, Virginia, USA
Pyrite (yellow-white, right) is fractured along its cleavage and rimmed by chalcopyrite (yellow) and inclusion-free sphalerite (light grey, bottom left). Pyrite encloses lath-shaped phyllosilicates (dark grey, centre). Silicates are dark grey. Black areas are polishing pits.
Polished block, plane polarized light, x 40, air