colcothar

[kol-kuh-ther]

noun

Chemistry.

1. the brownish-red oxide of iron produced by heating ferrous sulfate: used chiefly as a pigment in paints and theatrical rouge, and as a polishing agent.

colcothar

/ ˈkɒlkəˌθɑː /

noun

1. Also called: crocus. a finely powdered form of ferric oxide produced by heating ferric sulphate and used as a pigment and as jewellers' rouge

Word History and Origins

Origin of colcothar¹

1595–1605; < Medieval Latin < Old Spanish colcotar, Spanish Arabic qulquṭār, perhaps < Greek chálkanthos copper sulfate solution

Word History and Origins

Origin of colcothar¹

C17: from French colcotar, from Spanish colcótar, from Arabic dialect qulqutār

Example Sentences

Colcothar, kol′kō-thar, n. a dark-red iron peroxide formed by calcining copperas.

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The solution of iron in spirit of vitriol produces green copperas; which being calcined, becomes a red substance, called colcothar.

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Ferric oxide is known as colcothar, English-Roth, rouge, crocus, etc.

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Take two Ounces of Vinegar, a Dram of Colcothar, two Drams of Crocus Martis Astringens; beat the whole together, steeping Muscus Quercinus therein; then throw upon it the Powder of Mushrooms, or of Crepitus Lupi: Apply this Remedy, and you'll soon stop the H�morrhage, taking Care nevertheless to bind the Part well, otherwise the Astringents do not readily take Effect.

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Take Colcothar or Red Vitriol that remains in the Retort after the Spirit has been drawn off, Burnt Allom, and Sugar-candy, of each thirty Grains; the Urine of a Young Person, and Rose-Water, of each half an Ounce; and two Ounces of Plantain-Water: Let the whole Mixture be stirr'd about for a long time, and then put into a Vial.

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