Sphalerite, chalcopyrite and pyrite. Aarja, Oman
Sphalerite (grey, left) encloses poorly polished spherical pyrite (pale yellow, top left) and pyrite framboids (centre). It is intergrown with chalcopyrite (yellow, centre right), which encloses small euhedral pyrite crystals (centre right). The majority of the pyrite is poorly polished, and poorly crystalline cores are surrounded by euhedral, well crystalline margins (bottom right). Dark grey areas are quartz, black areas are polishing pits.
Polished block, plane polarized light, x 80, air