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

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.

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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.

From Project Gutenberg

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.

From Project Gutenberg