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.

Azurite precipitation occurs in pore spaces, fractures, and cavities of the subsurface rock. The resulting azurite is usually massive or nodular. In rare situations, azurite is found as stalactitic and botryoidal growths. Well-formed monoclinic crystals are infrequently found. These can only occur if azurite precipitates unrestricted in a fracture or cavity and is not disrupted by later crystallization or rock movements.

Malachite is another copper carbonate mineral that forms under conditions similar to azurite. These minerals are often found in the same deposit and are often intergrown with one another. This produces a material known as azurmalachite, which, when of high quality, can be used as a beautiful lapidary material.

In the United States, Arizona, New Mexico, and Utah are the notable locations for finding azurite. More important deposits have been found in France and Namibia. Noteworthy occurrences have been found in Mexico, Chile, Australia, Russia, and Morocco.