Adjacent Words

Colcothar definitions

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Webster's 1828 Dictionary

COLCOTHAR, n. The brown red oxyd of iron which remains after the distillation of the acid from sulphate of iron; used for polishing glass and other substances. It is called by artists crocus, or crocus martis.
The sulphate of iron is called colcothar or chalcite, when the calcination has been carried so far as to drive off a considerable part of the acid.

Webster's 1913 Dictionary

Colcothar Col"co*thar (k[o^]l"k[-o]*th[~e]r), n. [NL. colcothar vitrioli, fr. Ar. qolqo[.t]ar.] (Chem.) Polishing rouge; a reddish brown oxide of iron, used in polishing glass, and also as a pigment; -- called also crocus Martis.

Webster's 1913 Dictionary

Crocus Cro"cus (kr[=o]"k[u^]s), n. [L., saffron, fr. Gr. kro`kos; cf. Heb. kark[=o]m, Ar. kurkum, Skr. ku[.n]kuma.] 1. (Bot.) A genus of iridaceous plants, with pretty blossoms rising separately from the bulb or corm. C. vernus is one of the earliest of spring-blooming flowers; C. sativus produces the saffron, and blossoms in the autumn. 2. (Chem.) A deep yellow powder; the oxide of some metal calcined to a red or deep yellow color; esp., the oxide of iron (Crocus of Mars or colcothar) thus produced from salts of iron, and used as a polishing powder. Crocus of Venus (Old Chem.), oxide of copper.