Contents

The copper ore from Kolihan, Rajasthan, India consists essentially of pyrrhotite and chalcopyrite with minor amounts of cubanite, mackinawite, vallerite, pyrite, marcasite, arsenopyrite, rammelsbergite, sphalerite, tetrahedrite, magnetite, ilmenite and an un-identified mineral "X. " Three structural types of pyrrhotite--monoclinic, hexagonal and troilite as well as intergrowths of monoclinic and hexagonal pyrrhotite and hexagonal pyrrhotite and troilite are observed. Cubanite also occurs in three structural types--isometric, tetragonal and orthorhombic. Mackinawite of both exsolution and replace-ment origin is present. There are several interesting unmixing textures. Chalcopyrite shows exsolution lamellae and grains of isometric, tetragonal and orthorhombic cubanire. Grains of orthorhombic cubanite show inversion twinning, and isometric and tetragonal cubanire lamellae show part inversion to the orthorhombic form. Chalcoyprite has exsoltuion threads of mackinawire and stars, blebs and skeletal crystals of sphalerite. Some of the granular cubanite has exsolved wisps of pyrrhotite. Hexagonal pyrrhotite show