ochre

Ochre is a natural earth pigment composed primarily of hydrated iron oxide. It appears in a range of colors from pale yellow to deep orange and red to brown, depending on its iron oxide content and hydration level. The color derives mainly from goethite (yellowish) and hematite (reddish); limonite can contribute yellow to brown tones.

Ochre pigments may contain clay, silica, or other minerals as impurities, which influence texture and hue. In geology and mineralogy, ochre refers to a family of pigments rather than a single mineral; it is often described as a naturally occurring iron oxide pigment.

Ochre deposits are widespread worldwide, with historic sources including regions such as Roussillon in southern France and various sites in Spain, Africa, and Australia. It has been quarried and ground to powders for millennia; to adjust color, ochre can be calcined (heated) to deepen the red tones. Modern artists use both raw and calcined ochre.

Ochre is among the earliest pigments used by humans, appearing in cave paintings in Africa and Europe, as well as in ancient Egypt, Mesopotamia, and the Mediterranean. It has also served as body paint, cosmetics, and architectural color. In contemporary art and industry, ochre remains a common pigment for paints, coatings, pottery glazes, and decorative applications.

As a pigment, ochre is valued for its relative safety and lightfastness. It is insoluble, chemically stable, and can be mixed with oil, resin, or acrylic binders. In some jurisdictions, iron oxide pigments are approved colorants for certain foods and cosmetics, reflecting their widespread and long-standing use.