High Quality Content by WIKIPEDIA articles! Egyptian blue is chemically known as calcium copper silicate (CaCuSi4O10 or CaO·CuO·4SiO2). It is a pigment used by Egyptians for thousands of years. It is considered to be the first synthetic pigment. The pigment was known to the Romans by the name caeruleum. Vitruvius describes in his work `"De architectura" how it was produced by grinding sand, copper and natron and heating the mixture, shaped into small balls, in a furnace. Lime is necessary for the production as well, but probably lime-rich sand was used. After the Roman era, Egyptian Blue fell from usage and the manner of its creation forgotten.