Malachite - Wikipedia
Malachite is a copper carbonate hydroxide mineral, with the formula Cu 2 CO 3 2.This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation.