Azure ( , ) is the color between cyan and blue on the spectrum of visible light. It is often described as the color of the sky on a clear day. On the RGB color wheel, "azure" (hexadecimal #0080FF) is defined as the color at 210 degrees, i.e., the hue halfway between blue and cyan. In the RGB color model, used to create all the colors on a television or computer screen, azure is created by adding a 50% of green light to a 100% of blue light. In the X11 color system, which became a model for early web colors, azure is depicted as a pale cyan or white cyan. Etymology and history The color azure ultimately takes its name from the intense blue mineral lapis lazuli. is the Latin word for "stone" and is the genitive form of the Medieval Latin , which is taken from the Arabic lāzaward, itself from the Persian lāžaward, which is the name of the stone in Persian and also of a place where lapis lazuli was mined. The name of the stone came to be associated with its color. The French , the Italian , the Polish , Romanian and , the Portuguese and Spanish , Hungarian , and the Catalan atzur, all come from the name and color of lapis lazuli. The word was adopted into English from the French, and the first recorded use of it as a color name in English was in 1374 in Geoffrey Chaucer's work Troilus and Criseyde, where he refers to "a broche, gold and asure" (a brooch, gold and azure). Some languages, such as Italian, generally consider azure to be a basic colour, separate and distinct from blue. Some sources even go to the point of defining blue as a darker shade of azure. 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. The use of the term spread through the practice of heraldry, where "azure" represents a blue color in the system of tinctures. In engravings, it is represented as a region of parallel horizontal lines, or by the abbreviation az. or b.