Malachite

Malachite is a green carbonate mineral (basic copper(II) carbonate) with hardness between 3.5 and 4 on the Mohs scale. It crystallizes in the monoclinic crystal system. Malachite often results from weathering of copper ores and is often found together with goethite and calcite. It was used as a mineral pigment in green paints from antiquity until about 1800. The pigment is moderately lightfast, very sensitive to acids and varying in colour. The natural form was being replaced by its synthetic form, verditer amongst other synthetic greens.