Bornite, pyrite and chalcopyrite. Aarja, Oman
250µm
Fine-grained radiating pyrite (yellow-white, bottom right) is extensively replaced by bornite (centre top) to give lower reflectance cores to the 'pyrite'. Coarser-grained bornite (brown, top right) is intergrown with chalcopyrite (yellow, centre) and cements pyrite aggregates. Black areas are polishing pits.
Polished block, plane polarized light, x 80, air
