Azurite (pigment)

Azurite is an inorganic pigment derived from the mineral of the same name.[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.[2] Azurite pigment typically includes traces of malachite and cuprite; both minerals are found alongside azurite in nature, and they may account for some of the green discoloration of the pigment.[1]^: 26 The particle size of azurite pigment has been shown to have a significant effect on its chromatic intensity, and the manner of grinding and preparing the pigment therefore has a major impact on its appearance.[3]

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  Michelangelo, The Entombment, ca. 1500–1501. The azure blue in the drapery has turned green in time.
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  Albrecht Altdorfer, Christ Taking Leave of His Mother, ca. 1520. The blue color of the clothing and sky is derived exclusively from azurite.