Azure is a color that is commonly compared to the color of the sky on a clear summer's day.

In the X11 color system which became a standard for early web colors, azure is depicted as a pale cyan color.

Azure also describes the color of the mineral azurite, both in its natural form and as a pigment in various paint formulations. In order to preserve its deep color, azurite was ground coarsely. Fine-ground azurite produces a lighter, washed-out color. Traditionally, the pigment was considered unstable in oil paints, and was sometimes isolated from other colors and not mixed. Modern investigation of old paintings, however, shows that the pigment is very stable unless exposed to sulfur fumes.