Pyrite, chalcopyrite, spinel, altered pentlandite and native gold. Kambalda, Western Australia
Coarse-grained pyrite (light yellow-white, left) is intergrown and replaced by chalcopyrite (dull yellow, right). Euhedral to subhedral spinel crystals, (light grey, left centre) occur within pyrite and chalcopyrite. Native gold (golden yellow, very high reflectance, centre) makes the sulphides appear dull. Pentlandite (brown-pink, top left) is present but is extensively altered to violarite.
Polished block, plane polarized light, x 80, air