“SEM micrograph (BSE mode) of a polished ore sample showing two concentrically zoned pyrite spherules (the slightly brighter core contains traces of Pb, Ag, Cu and As, probably all as nano-inclusions) in sphalerite (grey), with minor galena (white) and quartz (black). Natural History Museum Vienna collection, catalogue no. E 6202 (dark, fine-grained, massive ore). ”

“SEM micrograph (SE mode) of a polished ore sample showing two concentrically zoned pyrite spherules (the slightly brighter core contains traces of Pb, Ag, Cu and As, probably all as nano-inclusions) in sphalerite (grey), with minor galena (white) and quartz (black). Note the distinctly higher hardness of the pyrite. Natural History Museum Vienna collection, catalogue no. E 6202 (dark, fine-grained, massive ore). ”