Azurite

Azurite is a copper carbonate hydroxide mineral with a chemical composition of Cu3(CO3)2(OH)2. It is best known for its characteristic deep blue to violet-blue color. The blue color, known as "azure," is like the deep blue evening skies often seen above deserts and winter landscapes. It has been used by people in many parts of the world for thousands of years. Ancient people used it as an ore of copper, as a pigment, as a gemstone, and as an ornamental stone.

Azurite is a secondary mineral that usually forms when carbon-dioxide- laden waters descend into the Earth and react with subsurface copper ores. The carbonic acid of these waters dissolves small amounts of copper from the ore. The dissolved copper is transported with the water until it reaches a new geochemical environment. This new environment could be a location where water chemistry or temperature changes, or where evaporation occurs. If conditions are right, the mineral azurite might form.

If these conditions persist for a long time, a significant accumulation of azurite might develop. This has occurred in many parts of the world including Mexico, Chile, Australia, Russia, Morocco and the United States.