Description
The mineral azurite is a copper carbonate with the chemical formula Cu3(CO3)2(OH)2. The typically transparent to translucent azurite has a light blue streak color, a vitreous luster, and a monoclinic crystal system. Its average density is 3.83 and its hardness is 3.5 to 4. Azurite is not radioactive and bright blue to dark purple pleochroic. The name azurite is derived from the Persian word lazhward, meaning "blue." The very common azurite occurs primarily in the oxidized portions of copper deposits or as a secondary mineral in carbonate-rich waters. It also forms when copper-bearing solutions react with limestone. The type locality of azurite is Chessy-les-Mines, Rhône-Alpes, France. Azurite has been used for centuries as a blue pigment. It was formerly known as Azurro Della Magna (from the Italian). When mixed with oil, it turns slightly green. When mixed with egg yolk, it turns grayish-green. Azurite is often used in jewelry and is a popular mineral among collectors.
