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Ochre pigment. Ochre (/ ˈ oʊ k ər / OH-kər; from Ancient Greek ὤχρα (ṓkhra), from ὠχρός (ōkhrós) 'pale'), iron ochre, or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. [2] It ranges in colour from yellow to deep orange or brown.
Red ochre takes its reddish colour from the mineral hematite, which is an anhydrous iron oxide, and the main ingredient of rust.It was one of the earliest pigments used by man.
The golden ochre pigment is a natural mixture that consists primarily of crystalline iron oxide hydrate with some clay.The closest to golden ochre among related minerals is light ochre, which has a less warm and rich color.
The anhydrous pigment has a dark purple-red or maroon color, hydrates' colors vary from dull yellow (yellow ochre) to warm red. [1]The iron oxide red is extremely stable: it is not affected by light and most chemicals (soluble in hot concentrated acids); heat only affects the hydrated variants (the water is removed, and the color darkens).
Chromium pigments. Chrome yellow or crocoite (PY34): lead chromate (PbCrO 4). Strontium yellow (PY32): SrCrO 4; Cobalt pigments. Aureolin or cobalt yellow (PY40): potassium cobaltinitrite (K 3 Co(NO 2) 6). Iron pigments. Yellow ochre (PY43): a naturally occurring clay of monohydrated ferric oxide (Fe 2 O 3 ·H 2 O). Lead pigments. Naples yellow ...
Pigments and paint grinding equipment believed to be between 350,000 and 400,000 years old have been reported in a cave at Twin Rivers, near Lusaka, Zambia. Ochre, iron oxide, was the first color of paint. [7] A favored blue pigment was derived from lapis lazuli. Pigments based on minerals and clays often bear the name of the city or region ...
Earth pigments are naturally occurring minerals that have been used since prehistoric times as pigments. Among the primary types of earth pigments include the reddish-brown ochres , siennas , and umbers , which contain various amounts of iron oxides and manganese oxides .
Goethite is an important component of ochre pigments, [21] and has been heat-treated for use as a red pigment since Paleolithic times. [22] Iron-rich lateritic soils that have developed over serpentinite rocks in tropical climates are mined for their iron content, as well as other metals. [23]