Porous nodules composed essentially of cellular pyrite . . . appear to occupy relatively smooth-walled cavities within massive chalcopyrite, from which they may be readily separated and removed in places almost intact. Platy ribs and seams of pyrite extend from the nodules into the enclosing mosaic of chalcopyrite crystals, within which they assume a delicate rhombohedral pattern, formed by an intersecting network of chains of minute pyrite cubes. The textural relationships described and illustrated suggest that the nodules may have been formed by recrystallization of pyrite-carbonate-silicate material that was engulfed by fluid magmatic chalcopyrite ore.