Pyrite, stromeyerite, bornite and tetrahedrite group mineral. Unknown Provenance
Euhedral to subhedral pyrite (light yellow-white, bottom left) is replaced by copper-silver sulphides and is associated with tetrahedrite (green-grey, centre top). Bornite (brown, centre top) is intergrown with stromeyerite which shows strong reflection pleochroism from blue-lilac (top left) to light purple (centre right). Black areas are polishing pits. Pyrite is scratched (centre left), showing the effect of incomplete polishing at coarser grades leaving relict scratches not removed by later polishing with finer grades of polishing paste.
Polished block, plane polarized light, x 80, air