The mineral malachite is a basic carbonate of copper corresponding to the formula Cu2(CO3)(OH)2. It is monoclinic, crystals tending to be acicular, but usually found massive. It is a brittle mineral; hardness, 3.5–4; specific gravity, 4.05; luster, vitreous to silky or dull; color, green; streak, green; translucent to opaque. Malachite is an alternation product found associated with other copper-bearing minerals.
