Galena, chalcopyrite, sphalerite and pyrite. Ainai Mine, Akita Prefecture, Japan
Repolished after etching. Galena (blue-white) forms complex intergrowths with chalcopyrite (yellow, centre) and sphalerite (light grey, right). Small subhedral pyrite crystals (light yellow-white, centre top) show high reflectance. Etching has shown the galena to comprise small polygonal crystals with 120' angles (centre top, centre bottom). Very small tetrahedrite crystals occur within galena (light grey, higher reflectance than sphalerite, left centre).
Polished block, plane polarized light, x 280, air