Brochantite

Crystals of brochantite can range from emerald green to black-green to blue-green, and can be acicular or prismatic. Brochantite is often associated with minerals such as malachite, azurite, and chrysocolla, and may form pseudomorphs with these minerals.

The mineral is found in a number of locations around the world, notably the southwestern United States (especially Arizona), Serifos in Greece and Chile.

Brochantite is a common corrosion product on bronze sculptures located in urban areas, where atmospheric sulfur dioxide (a common pollutant) is present. Brochantite forms mainly in exposed areas where weathering prevents accumulation copper ions and enhancement in the acidity of water films. In sheltered areas, the main corrosion product is antlerite.

Brochantite veins were mined for copper in Chuquicamata, Chile, from 1879 until 1912 when a more indiscriminate large-scale mining of low-grade ores began at the mine.