Chalcopyrite, pyrite, stannite group mineral, arsenopyrite and covelline. Wheal Jane, Cornwall, Britain
250µm
A single euhedral pyrite (light yellow-white, centre) and subhedral to anhedral arsenopyrite grains (white, higher reflectance than pyrite, bottom centre) are enclosed within chalcopyrite (yellow, left). Chalcopyrite is rimmed by a stannite group mineral (pink-brown, centre), which is inclusion-free, but is also altered to covelline (deep blue, centre right). Quartz is dark grey and well polished (bottom right); chlorite is poorly polished and has lower reflectance than quartz (right centre). Black areas are polishing pits.
Polished block, plane polarized light, x 80, air
