- 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.
Origin of colcothar
Examples from the Web for colcothar
Historical Examples of colcothar
A factitious article is prepared by calcining a mixture of colcothar and red ochre.Cooley's Practical Receipts, Volume II
When this Colcothar hath undergone a violent fire, as in the experiment now related, scarce any Acid remains therein.Elements of the Theory and Practice of Chymistry, 5th ed.
Pierre Joseph Macquer
The wooden disc is also employed for this purpose with putty, colcothar, or washed tripoli.
When the cork or wooden disc edged with hat felt is used for polishing, putty or colcothar is applied to it.
Emery with oil is used for grinding down, and tin-putty or colcothar for polishing.
- a finely powdered form of ferric oxide produced by heating ferric sulphate and used as a pigment and as jewellers' rougeAlso called: crocus