Pyrrhotite, sphalerite, chalcopyrite and graphite. Great Gossan Lead, Virgi
250µm
Pyrrhotite (brown) shows deformation twin lamellae (higher reflectance, centre top) and plucking along its (0001) cleavage (black pits, centre top). Both inclusion-free sphalerite (light grey, centre bottom) and sphalerite with abundant chalcopyrite (yellow) inclusions along crystallographic directions (top right) are present. A curved flake of graphite (brown, low reflectance, centre) lies across a pyrrhotite-sphalerite junction close to a silicate grain. Black areas are polishing pits.
Polished block, plane polarized light, x 80, air
