The term ore mineral usually refers to a mineral from which one or more useful industrial metals can be extracted. For example, chalcopyrite and galena are ore minerals of copper and lead, respectively. Ore minerals are sometimes natural metals, such as gold and platinum, but most ores are compounds. Most industrial metals are refined from metal ores, and a single metal element can be extracted from several types of ores. For example, copper can be refined from chalcocite, bornite, chalcopyrite, cuprite, native copper and malachite. Some minerals can be used to extract two or more types of metal elements, such as carnotite, which is used for the extraction of uranium and vanadium.