Azurite

Azurite is a azure-blue copper mineral produced by weathering of copper ore deposits. It is also known as Chessylite after a particular type found at the Chessy-les-Mines near Lyon in France. When water is absorbed by Azurite it forms Malachite and the two are frequently found together. This also occurs with chrysocolla and turquoise in areas of copper deposits.

Azurite is used occasionally as beaded jewellery and as an ornamental stone. However it has a softness and tendency to lose its deep blue colour as it weathers makes it not a desirable stone to use in jewellery. The gemstone can be easily destroyed by heat, losing carbon dioxide and water to form black, powdery copper oxide. Therefore all mounting must be done at room temperature. The intense color of azurite makes it a popular collector’s stone. However, bright light, heat, and open air all tend to reduce the intensity of its color over time.

Different sources claim the name is derived from the Persian word lazhward or from the Arabic word azul, both of which mean blue. The mineral has also been known since ancient times and under the Greek name Kuanos, meaning ‘deep blue’.

It is not known widely as a birthstone, but several references indicate it may have been used as a birthstone for the sign of Taurus.

Another use of Azurite is pigment. In the Middle Ages and Renaissance it was ground into pigment for use in paint and eye shadow. When mixed with oil it turns slightly green. When mixed with egg yolk it turns green-grey. Older examples of azurite pigment may show a more greenish tint due to weathering into malachite.