Bornite

Bornite is a mineral composed of copper iron sulfide (Cu₅FeS₄), recognizable by its spectacular iridescence with blue, purple, red, green, and golden hues. When freshly broken, it has a copper-brown color, but its natural oxidation gives it its famous multicolored appearance, earning it the nickname "Peacock Ore". Found in hydrothermal copper deposits, bornite is often associated with chalcopyrite, pyrite, or chalcocite.