Malachite is a carbonate mineral normally known as "copper carbonate" with the formula Cu2CO3(OH)2. This green-colore mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur.