Virtual Atlas of Opaque and Ore Minerals
Digenite, bornite, haematite, covelline, wittichenite and chalcopyrite. English Lake District, Britain
Digenite (light blue, top) is replaced along cleavage by covelline (dark blue, centre left) and along grain boundaries by bornite (orange-brown, centre). A vein cross-cutting digenite is infilled with wittichenite (white, top left). Fine-grained haematite (green-grey) replaces copper and copper-iron sulphides (especially bottom right). Very fine-grained banded haematite (green-grey, low reflectance, centre) is associated with quartz (dark grey). Minor amounts of chalcopyrite (yellow, centre bottom) are surrounded by a haematite rim. Black areas are polishing pits. Quartz (dark grey) is the main gangue phase.
Polished block, plane polarized light, x 80, air