Azurite (pigment)

[1] It was likely used by artists as early as the Fourth Dynasty in Egypt, but it was less frequently employed than synthetically produced copper pigments such as Egyptian Blue.

[1]: 23–26  In the Middle Ages and Renaissance, it was the most prevalent blue pigment in European paintings, appearing more commonly than the more expensive ultramarine.

[1]: 26  Azurite's derivation from copper mines tends to give it a greenish hue, in contrast with the more violet tone of ultramarine.

[2] Azurite is also less stable than ultramarine, and notable paintings such as Michelangelo's The Entombment have seen their azure blues turn to olive green in time.

[1] Azurite was frequently used in East Asia, but is less commonly found in Pre-Columbian indigenous and later Spanish Mission Church paintings.

[6] Paratacamite and atacamite are two different phases of a basic copper chloride that are both formed through the degradation of azurite; they can be distinguished using FTIR techniques.

[6] Rather, the dark blue compound is produced due to the action of barium hydroxide, and not ammonium carbonate, although both are present in the typical conservation technique used to restore azurite.

Artists employed special techniques which required training to grind the pigment in order to achieve different intensities.

[1] Azurite particles are irregular in size and often contains impurities such as malachite and cuprite due to its close association with these compounds.

[1] In the 1520 painting titled Christ Taking Leave of His Mother by Albrecht Altdorfer, azurite is used in the blue garments of the figures.