Ochre or Ocher (pronounced //, from the Greek ?????, yellow) is a color, usually described as golden-yellow or light yellow brown.
Pigment
As a painting pigment, it exists in at least four forms:
Yellow ochre, Fe2O3 ? H2O, a hydrated Iron oxide
Red ochre, Fe2O3, chemically identical to yellow ochre, but reddened through heating
Purple ochre, identical to red ochre chemically but of a different hue caused by different light diffraction properties associated with a greater average particle size
Brown ochre (Goethite), also partly hydrated iron oxide (rust)
For further information, see the articles on the individual ochres.They are found throughout the world in many shades. Many sources consider the best brown ochre to come from Cyprus, and the best yellow and red ochre from Roussillon, France. All have been used since prehistoric times, and are among the oldest pigments used.
Industry
When the mineral was found in Brixham England, it became a very important part of the develo
Source:
http://en.wikipedia.org/wiki/Ochre