Chalcopyrite, arsenopyrite, pyrite, sphalerite and native gold. Clogau Mine, Wales, Britain
Arsenopyrite (white, centre) is highly fractured and these fractures are infilled by sphalerite (light grey, centre left), native gold (yellow-white, high reflectance, poorly polished, centre) and chalcopyrite (yellow). Chalcopyrite also encloses much of the arsenopyrite. A euhedral cube of pyrite (light yellow-white, right centre) has lower reflectance than arsenopyrite. Dark grey area is quartz (bottom). The native gold is 950 fine, and to the eye has a higher reflectance than the photomicrograph would suggest.
Polished block, plane polarized light, x 80, air