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Webster 1913 Edition


Colcothar

Col′co-thar

(kŏl′kō̍-thẽr)
,
Noun.
[NL.
colcothar vitrioli
, fr. Ar.
qolqoṭar
.]
(Chem.)
Polishing rouge; a reddish brown oxide of iron, used in polishing glass, and also as a pigment; – called also
crocus Martis
.

Webster 1828 Edition


Colcothar

COLCOTHAR

,
Noun.
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.

Definition 2024


colcothar

colcothar

English

Noun

colcothar (countable and uncountable, plural colcothars)

  1. (organic chemistry, obsolete) Polishing rouge; a reddish-brown oxide of iron, used in polishing glass, and also as a pigment; crocus Martis.