Ochre
Ochre (spelled Ocher in American engllsh) normally refers to a pigment associated with natural earth because it consists of a clay base which has a range of colours described as yellow ochre, red ochre, brown ochre, purple ochre, sienna ochre and umber ochre.
A yellow ochre, is yellow from the mineral goethite, an iron oxide hydroxide (limonite). Red ochre, takes its red colour from the mineral hematite, which is an anhydrous iron oxide. Brown ochre, takes its colour from goethite, a partly hydrated iron oxide. Whilst sienna and umber ochres take their colours from differing amounts of manganese oxide.
The use of red ochre pigments have been dated by archaeologists as early as 300,000 years ago, around the time of the emergence of Homo sapiens. The use
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