Cerulean

The color cerulean (American English), or caerulean (British English, Commonwealth English), is a variety of the hue of blue that may range from a light azure blue to a more intense sky blue. Cerulean may also be mixed with the hue of green. The first recorded use of cerulean as a color name in English was in 1590. The word is derived from the Latin word caeruleus (Latin: [kaeˈruleus]), "dark blue, blue, or blue-green", which in turn probably derives from caerulum, diminutive of caelum, "heaven, sky". "Cerulean blue" is the name of a blue-green pigment consisting of cobalt stannate (Co2SnO4). The pigment was first synthesized in the late eighteenth century by Albrecht Höpfner, a Swiss chemist, and it was known as Höpfner blue during the first half of the nineteenth century. Art suppliers began referring to cobalt stannate as cerulean in the second half of the nineteenth century. It was not widely used by artists until the 1870s when it became available in oil paint.