Pyrrhotite, magnetite, pentlandite and chalcopyrite. Strathcona Mine, Sudbury, Ontario, Canada
Pyrrhotite crystals (light brown) have granular pentlandite crystals (light brown, higher reflectance, centre left) along their grain boundaries but are free of flame-like exsolution bodies of pentlandite. Magnetite (grey, bottom left) encloses a crystal of chalcopyrite (yellow, bottom left). Black areas are polishing pits.
Polished block, plane polarized light, x 80, air