Ochre (also spelled ocher) is a natural earth pigment composed mainly of hydrated iron oxide mixed with varying amounts of clay or sand. It ranges in color from pale yellow to deep orange or brown, and can appear red when a larger proportion of hematite (iron oxide) is present. The name derives from the Greek word for yellow, ochros. Ochre has been used since prehistoric times for body painting, cave art, and as a pigment in paints, cosmetics, and various decorative applications. It occurs in many archaeological and geological deposits worldwide and can be artificially produced by calcining or processing natural ochre to achieve different hues such as Mars yellow, Mars orange, violet, or red ochre.