Malaquita

Malachite is a secondary copper hydroxycarbonate that forms in the oxidation zone of copper deposits, including hydrothermal deposits.

It shows botryoidal and fibrous habits; locally it may develop microbotryoidal textures. In the Kolwezi area it develops acicular aggregates with silky lustre and very intense green colour. Its colour and botryoidal texture have made it valued by collectors. It has been valued since antiquity.

It is the less carbonated term of the malachite–azurite pair. In Kerrouchene, pseudomorphs after azurite are common: the compositional unit changes, but the outline of the earlier crystal is retained. At surface, azurite can lose CO₂ readily; with circulating water and an open system, the dissolved CO₂ escapes and malachite is more stable. Azurite reorganises and transforms into malachite; the reverse process seldom occurs naturally.

← Periodic table of the collection