Covelline, blaubleibender covelline, djurleite and chalcopyrite. Mount Gabriel. County Cork, Ireland
Djurleite (white, centre) is replaced by bladed covelline (purple-blue). Other grains (bottom left) are replaced by a mixture of blaubleibender covelline (light blue) and covelline (red-purple). Minor amounts of chalcopyrite (yellow, bottom centre) are replaced by covelline. Djurleite in this ore is light sensitive (not-shown), suggesting that silver minerals are associated with it. Malachite (light and dark grey) forms radiating crystal aggregates (bottom left), and shows clear bireflectance between adjacent crystals and faint green internal reflections (top right). Black areas are polishing pits.
Polished block, plane polarized light, x 180, oil