“Cubic crystals of pyrite, pseudomorphs after pyrrhotite, on colorless crystals of quartz. At high magnification, the striations of the cube faces are opposite, as in pyrite, enabling you to distinguish it from arsenopyrite, most evident in the two cubes, with surfaces modified by the octahedron, located to the left of the picture. Collection and photo of Gianfranco Ciccolini. Nikon D610, bellows, Schneider Kreuznach 28mm; f:4. Focal using 5.6.”