Malachite is a copper carbonate mineral with the formula Cu2CO3(OH)2 Classed as a secondary mineral of copper, it occurs in the weathering zone, in proximity to major ore bodies. In it's purest form it contains 57% of pure copper, but this is not generally exploited because it is not plentiful enough, and because there is poor metallurgical recovery. It is quite a dense mineral with an s.g. of 3.6 to 4. and a hardness of 3.5 to 4. This polished slab appears to be a broken portion of a nugget, and is only known to have come from Brazil.