Pigmento de Marte

"Mars" is now the common name used for synthetic iron oxide pigments. Mars colors are made from hydrated iron oxide co-precipitated with alum using lime or potash. The proportion of the mixture controls the degree of color; drying the product produces Mars yellow, other colors include orange, red, black, brown, and violet, produced by calcining the yellow. "Mars" was originally a brand name in the late 18th century.