Digenite, bornite, haematite and chalcopyrite. English Lake District, Britain
500µm
Digenite (blue, top left) shows minor replacement by covelline (deep blue) along cleavage and small fractures. More extensive replacement is shown by bornite (brown-pink, centre) which contains relict digenite. Minor amounts of chalcopyrite (yellow, right centre) occur on the edge of bornite but are difficult to see. Two distinct generations of haematite are present. Haematite laths (light blue, hard, centre bottom) occur within digenite and bornite, whereas most haematite (green-grey) is very fine-grained and replaces bornite along grain edges (bottom centre). Quartz is dark grey.
Polished block, plane polarized light, x 40, air
