Chromite, pentlandite, violarite and rutile. Bushveld, Republic of South Africa
Euhedral chromite crystals (green-grey) enclose exsolved fine rutile needles (light grey, right) which are crystallographically oriented along (111) planes of the chromite. Coarse-grained rutile crystals (light grey, top centre and bottom left) overgrow chromite. Interstitial pentlandite (light-brown, centre) has partially altered along its cleavage to less well polished violarite (brown, lower reflectance than pentlandite). The silicate matrix is black.
Polished block, plane polarized light, x 160, oil