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

The wooden disc is also employed for this purpose with putty, colcothar, or washed tripoli.

From Project Gutenberg

When the cork or wooden disc edged with hat felt is used for polishing, putty or colcothar is applied to it.

From Project Gutenberg

No additional colcothar after the first is required in this part of the process; but only a drop of water from time to time.

From Project Gutenberg

Emery with oil is used for grinding down, and tin-putty or colcothar for polishing.

From Project Gutenberg

Colcothar of Vitriol, and Crocus of Mars, are old names for red oxide of iron.

From Project Gutenberg