Chalcopyrite: Gemstones Information
Chalcopyrite is CuFeS2 and forms equant tetrahedral-shaped crystals often with modification by scalenohedral faces; it also forms compact masses. Chalcopyrite has a metallic lustre though brass-yellow often shows tarnish and iridescence. The hardness is 3.5–4 and the SG 4.1–4.3. It is sometimes used for cabochons though specimens are more often sought in their original state. Chalcopyrite occurs as a primary mineral in hydrothermal veins and in other environments. The occurrence is worldwide.