AZURITE
Composition: Cu3(CO3)2(OH)2
Crystal System: Monoclinic
Color: Azure blue, light blue
Type Locality: Chessy-les-Mines, Rhône, France
Azurite is a carbonate of copper. The name comes from the Persian lazhward, “blue,” an allusion to its color. It is found in the oxidized zone of copper-bearing ore deposits. Azurite most often occurs with the green copper carbonate, malachite, and other secondary copper, lead, and zinc minerals.
Azurite is fairly unstable; it needs a very specific set of conditions to form (acidic and high-carbonate fluids). Malachite, on the other hand, is more stable and forms over a wider range of conditions, hence it is more common. If conditions change after the formation of azurite, it may be partially or totally replaced (pseudomorphed) by malachite. Azurite almost never replaces malachite
 Azurite, Tsumeb. Photo by Ben Schumer.
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 Azurite, Bisbee, Cochise County, Arizona. Photo by Ben Schumer. |
 Malachite and Azurite, Robinson district, White Pine County, Nevada. Photo by Ben Schumer.
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 Azurite crystals on calcite and malachite. Bisbee, Cochise County, Arizona. Photo by Ben Schumer. |