malachite, a mineral, the green basic carbonate of copper occurring in crystals of the monoclinic system or (more usually) in masses. It is translucent or opaque; the luster is silky, vitreous, adamantine, or dull. It takes a good polish. An important ore of copper, it also serves as a gem and for various ornamental purposes and, when finely ground, as a pigment. It is found associated with other ores of copper (especially azurite) in various parts of the United States and in Chile, Russia, Congo (Kinshasa), Zimbabwe, and Australia.