Malachite is a copper carbonate hydroxide with a formula of Cu2CO3(OH)2. Chrysocolla is a hydrated copper phyllosilicate mineral, and mineraloid. The formula is highly complex, and so it is omitted. This specimen of unknown origin is composed of a bed of very dark green microcystalline crystals of malachite, overlain with an encrustation of mineraloid chrysocolla in very small botriodal form.