Chalcopyrite, pyrite, sphalerite and stannite. Neves-Corvo, Portugal
Subhedral to euhedral pyrite (light yellow-white, high reflectance, centre top) is partially replaced by chalcopyrite (bottom left). Chalcopyrite (yellow) is intergrown with sphalerite (light grey, centre) and stannite (brown, centre, left). Intergrowths between sphalerite and stannite are complex but much stannite forms rims between sphalerite and chalcopyrite (centre). Dark greys are rhombic carbonates (right centre) and silicate (darker grey, centre bottom). Black areas are polishing pits.
Polished block, plane polarized light, x 160, air