Sphalerite, tetrahedrite group, bournonite, chalcopyrite and galena. Broken Hill, New South Wales, Australia
Sphalerite (grey, right) is partially rimmed by chalcopyrite (yellow, bottom left) and bournonite (blue-white, centre)Tetrahedrite (light brown-grey, centre) is enclosed within a rim of bournonite (blue-white), which has a slightly lower reflectance, but is better polished than the isolated crystal of galena (white, centre left). Dark grey area is gangue. Black areas are polishing pits.
Polished block, plane polarized light, x 160, oil