Pyrite, sphalerite, chalcopyrite, galena and limonite. Jersey, Channel Islands, Britain
Pyrite (light yellow-white) encloses sphalerite stars (grey, centre, centre left) and minor amounts of poorly polished galena (white, top centre below chalcopyrite). Chalcopyrite (yellow, top right above galena) surrounds pyrite and is extensively altered to banded limonite (medium grey, right centre) which is intergrown with very finely disseminated chalcocite (blue-grey). Quartz (left centre) and phyllosilicate (dark grey) are the gangue phases. The presence of sphalerite stars which are typical of sphalerite exsolution in chalcopyrite, but are not common in pyrite, suggests that this pyrite has pseudomorphed chalcopyrite.
Polished block, plane polarized light, x 160, air