Galena, chalcopyrite, tetrahedrite and covelline. Clevedon, Somerset, Britain
Galena (white, bottom left) is rimmed by chalcopyrite (yellow) and also encloses it (top right). Tetrahedrite (light grey, centre) is intergrown with chalcopyrite which is partially replaced by covelline (deep blue, top left, bottom right). Baryte (dark grey) is the gangue.
Polished thin section, plane polarized light, x 55, air