Armenian Purple Ocher is a natural earth containing clay tinted by iron oxide that gives an exceptionally cool purple red hue. Our Armenian Purple Ocher contains about 13% iron oxide and 49% silica. Purple Ocher is obtained from iron ore deposits near Lori, Armenia.
|Alternate Names: ||Mars Red is the name given to the synthetic precipitated form of iron oxide. |
Origin and History
Red ocher is a natural earth containing clay tinted by iron oxide and is composed of a naturally calcined form of hematite, and traces of gypsum (calcium sulfate) or calcite (calcium carbonate). Hematite is a mineral composed of iron oxide minerals (α-Fe2O3) that occur as natural earth. Depending upon the content of iron oxide and other minerals, the color of red ocher varies from deep red to brownish red. Red iron oxide minerals, such as hematite, are found around the world and have been used as pigments since prehistory.
Permanence and Compatibility
Red ochers are among the most permanent colors among the artist's palette. It is compatible with all other pigments, and can be used with good results in all mediums.
Oil Absorption and Grinding
Red ochers absorb a medium amount of oil, which may slow the drying of oil paint, but because iron oxide is a drier in oil, it dries fast and forms an excellent film.
Red ochers are not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling the dust.
Pigment: Armenian Purple Ocher
|Color: ||Purple Red |
|Colour Index: ||Pigment Red 102 (77491) |
|Chemical Name: ||Iron Oxide |
|Chemical Formula: ||α-Fe2O3 |
|Chemical Composition |
|SiO2: ||48.5% |
|Al2O3: ||17.9% |
|Fe2O3: ||13.1% |
|MgO: ||7.43% |
|CaO: ||1.83% |
|ASTM Lightfastness Rating |
|Acrylic: ||I |
|Oil: ||I |
|Watercolor: ||I |
|Bulk Density: ||560 kg/cm3 |
|Tapped Density: ||710 kg/cm3 |
|Oil Absorption: ||26 g/100 g |
|Residual (Mesh 325): ||<0.1% |