Galena, cobaltite, tetradymite and pyrrhotite. Clogau Mine, Wales, Britain
Cobaltite (cream-white, hard, left) is intergrown with, and included within, galena (blue-white, centre). A lath-shaped crystal of pyrrhotite (brown, top centre) and a lath of tetradymite (green-white, higher reflectance than galena, oriented north-south, centre) are also enclosed within galena. Black area is quartz.
Polished block, plane polarized light, x 160, oil