colcothar

/kol-kuh-ther/US // ˈkɒl kə θər //UK // (ˈkɒlkəˌθɑː) //

钶钽铁氧体,钶钽铁合金,钶钽铁矿石,钶钽铁矿砂

Definitions

n.名词 noun

1
Chemistry.
- : 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.

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.
No additional colcothar after the first is required in this part of the process; but only a drop of water from time to time.
Emery with oil is used for grinding down, and tin-putty or colcothar for polishing.
Colcothar of Vitriol, and Crocus of Mars, are old names for red oxide of iron.