Ochre ( OH-kər; from Ancient Greek ὤχρα (ṓkhra) from ὠχρός (ōkhrós) 'pale') is a family of natural clay earth pigments, made up of ferric oxide and varying amounts of clay and sand, ranging in colour from yellow to deep orange or brown. The term is also used for the colours produced by this pigment, especially a light brownish-yellow. A variant of ochre containing a large amount of hematite, or dehydrated iron oxide, has a reddish tint known as red ochre (or, in some dialects in England, ruddle). The term "ochre" is colloquially used to cover a range of different substances used for their colours in Aboriginal Australian art and ceremonial decoration, for instance the clay known as "white ochre" or "pipe clay" is derived from kaolin or gypsum.
Terminology Ochre (sometimes "ocher" in American English,) is a natural clay earth pigment, consisting of a mixture of ferric oxide and varying amounts of clay and sand. The family of earth pigments known as ochre includes yellow ochre, red ochre, purple ochre, sienna, and umber. The major ingredient of all the ochres is iron(III) oxide-hydroxide, known as limonite, which gives them a yellow colour. A range of other minerals may also be included in the mixture: The clays coloured with iron oxide derived during the extraction of tin and copper may also be known as ochre. The term is also used for the colours produced by this pigment, especially a light brownish-yellow. The range of colours include:
Yellow ochre, FeO(OH)·nH2O - hydrated iron(III) oxyhydroxide (limonite) also called gold ochre. Red ochre, Fe2O3·nH2O, takes its reddish colour from the mineral hematite, which is an iron oxide, reddish brown when hydrated. Purple ochre is a rare variant 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, also FeO(OH), (goethite), is a partly hydrated iron oxide. Similarly, lepidocrocite — γ-FeO(OH), a secondary mineral, a product of the oxidation of iron ore minerals, found in brown iron ores Sienna contains both limonite and a small amount of manganese oxide (less than 5%), which makes it darker than ochre. Umber pigments contain a larger proportion of manganese (5-20%), which makes them a dark brown.
Historical use in art and culture
Prehistory
Over recent decades, red ochre has played a pivotal role in discussions about the cognitive and cultural evolution of early modern humans during the African Middle Stone Age. In Africa, evidence for the processing and use of red ochre pigments has been dated by archaeologists to around 300,000 years ago, the climax of the practice coinciding broadly with the emergence of Homo sapiens. Evidence of ochre's use in Australia is more recent, dated to 50,000 years ago, while new research has uncovered evidence in Asia that is dated to 40,000 years ago. Archeological evidence highlights that prehistoric populations picked different ochre specifically based on certain qualities such as their colour, texture, and even hardness. In parts of Southern Africa deep red-iron ochres were transported over very long distances even though there was evidence of local deposits, implying that each different pigment had a unique cultural or ritual importance to the people. The specific and purposeful movement of the ochre suggest there were many early long-distance exchange networks among the Middle Stone Age groups (Watts 2002).
A re-examination of artefacts uncovered in 1908 at Le Moustier rock shelters in France has identified Mousterian stone tools that were attached to grips made of ochre and bitumen. The grips were formulated with 55% ground goethite ochre and 45% cooked liquid bitumen to create a mouldable putty that hardened into handles. Earlier excavations at Le Moustier prevent conclusive identification of the archaeological culture and age, but the European Mousterian style of these tools suggests they are associated with Neanderthals during the late Middle Paleolithic, between 60,000 and 35,000 years before present. It is the earliest evidence of compound adhesive use in Europe. Pieces of ochre engraved with abstract designs have been found at the site of the Blombos Cave in South Africa, dated to around 75,000 years ago. "Mungo Man" (LM3) in Australia was buried sprinkled with red ochre around 40,000 years ago. In Wales, the Paleolithic burial called the Red Lady of Paviland from its coating of red ochre has been dated to around 33,000 years before present. Paintings of animals made with red and yellow ochre pigments have been found in Paleolithic sites at Pech Merle in France (ca. 25,000 years old), and the cave of Altamira in Spain (c. 16,500–15,000 BC). The cave of Lascaux has an image of a horse coloured with yellow ochre estimated to be 17,300 years old. Neolithic burials may have used red ochre pigments symbolically, either to represent a return to the earth or possibly as a form of ritual rebirth, in which the colour may symbolise blood and a hypothesised Great Goddess.
The use of ochre is particularly intensive: it is not unusual to find a layer of the cave floor impregnated with a purplish red to a depth of eight inches. The size of these ochre deposits raises a problem not yet solved. The colouring is so intense that practically all the loose ground seems to consist of ochre. One can imagine that the Aurignacians regularly painted their bodies red, dyed their animal skins, coated their weapons, and sprinkled the ground of their dwellings, and that a paste of ochre was used for decorative purposes in every phase of their domestic life. We must assume no less, if we are to account for the veritable mines of ochre on which some of them lived... The Gothic historian Jordanes claimed that the ancient Caledonians painted themselves "Iron Red", "whether by way of adornment or perhaps for some other reason". Ochre has uses other than as paint: "tribal peoples alive today . . . use either as a way to treat animal skins or else as an insect repellent, to staunch bleeding, or as protection from the sun. Ochre may have been the first medicament."
Ancient Egypt
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