Chalcopyrite, sphalerite, galena and covelline. Alderley Edge, Cheshire, Britain
250µm
Chalcopyrite (yellow, bottom) cements and replaces quartz (dark grey, centre top) and is itself replaced by covelline (deep blue, centre top left). Sphalerite (light grey, centre left, top centre) occurs about the margin of chalcopyrite. Galena (white, bottom left) also cements the silicates. Black areas are polishing pits.
Polished block, plane polarized light, x 80, air
