Chalcopyrite, sphalerite and pyrite. Jersey, Channel Islands, Britain
Chalcopyrite (yellow) contains exsolved sphalerite stars (light grey, centre) and two crystals of pyrite (light yellow, higher reflectance, top right) growing into a void (black). A very thin veinlet that is only just discernible (running north-south, centre) is marked by elongated polishing pits (black) and by stannite (light grey, higher reflectance than sphalerite, centre) cutting across the central sphalerite star. Black areas are polishing pits.
Polished block, plane polarized light, x 90, air