Chalcopyrite is a copper iron sulfide mineral (CuFeS2). Many pyrite-like minerals exist, such as pyrite, marcasite, arsenopyrite, pyrrhotite, and chalcopyrite. Chalcopyrite has a metallic luster, a deep yellowish-brassy color, a dark gray streak, a hardness of about 3.5 to 4, and no cleavage. Many specimens have a multicolored iridescent tarnish. Chalcopyrite is an important copper ore mineral.
Chalcopyrite (field of view ~4.5 cm) from the Sudbury Impact Crater in Ontario, Canada. The specimen really does look like this - better, in fact. This gorgeous rock comes from a massive sulfide vein hosted in Neoarchean-aged Levack Gneiss (2.64 to 2.71 billion years) from the Coleman Mine's 153 orebody (North Range, northwest of Sudbury, southeastern Ontario, Canada). Sulfide mineralization occurred during or very soon after the Sudbury impact event at 1.85 billion years (late Paleoproterozoic).