Description and Occurrence Malachite occurs when carbonated water interacts with copper minerals, or when a solution of copper interacts with limestone. It is a secondary mineral of copper, which means it's formed when copper minerals are altered by other chemicals.
Crystals sometimes form as needles that fan out from the rock in which they are embedded.
More often, malachite forms as a mass with concentric bands of light and dark green. Malachite is usually found with azurite, a blue secondary mineral of copper. A mineral sample can have alternating bands of green malachite and blue azurite. Malachite is used as a decorative stone, since it is easily cut and polished. While its softness limits its use as a gemstone, its beauty is hard to resist.