from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A brownish-red ferric oxide obtained as a residue after heating ferrous sulfate, used in glass polishing and as a pigment.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Polishing rouge; a reddish-brown oxide of iron, used in polishing glass, and also as a pigment; crocus Martis.

from the GNU version of the Collaborative International Dictionary of English

  • n. Polishing rouge; a reddish brown oxide of iron, used in polishing glass, and also as a pigment; -- called also crocus Martis.

from The Century Dictionary and Cyclopedia

  • n. The brownish-red peroxid of iron which remains after the distillation of the acid from iron sulphate.


Medieval Latin, from Spanish colcótar, from Arabic qulquṭār, possibly from Greek khalkanthos, copper sulfate : khalkos, copper + anthos, flower.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Arabic qolqotar. (Wiktionary)


  • Il est plus beau, plus vif que le brun-rouge d'Angleterre: Selon les uns, c'est une terre calcinée; selon d'autres, dont je crois l'opinion fondée, c'est le colcothar ou caput mortuum des eaux fortes qu'on réduit en poudre fine, après avoir bien lavées.

    The Creation of Color in Eighteenth-Century Europe

  • The colors used for this style of painting are zinc white, green oxide of chrome, cobalt green, chromate of lead, colcothar, ochers, and ultramarine.

    Scientific American Supplement, No. 483, April 4, 1885

  • The precipitates of gold, and the colcothar or other red preparations of iron, are called _tender_ colours.

    The Botanic Garden A Poem in Two Parts. Part 1: the Economy of Vegetation

  • There were pins and needles, yarn and thread, that have taken the place of the wilder thorn and fibre; all kinds of small hardware; looking-glasses in lacquered frames; beads of sorts, cowries and reels of cotton; pots of odorous pomatum and shea-butter nuts; feathers of the plantain-bird and country snuff-boxes of a chestnut-like fruit (a strychnine?) from which the powder is inhaled, _more majorum_, through a quill; physic-nuts (_tiglium_, or croton), a favourite but painful native remedy; horns of the goat and antelope, possibly intended for fetish 'medicine;' blue-stone, colcothar and other drugs.

    To the Gold Coast for Gold A Personal Narrative in Two Volumes.—Volume I


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  • "'There are two mortars with their pestles just below the colcothar of vitriol.'"
    --Patrick O'Brian, The Hundred Days, 43

    A Sea of Words: Colcothar of vitriol: A powdery reddish or purple substance used as an emetic. (p. 151)

    March 20, 2008