a brownish-red oxide of iron, obtained by heating ferrous sulfate: it is used as a pigment, polishing agent, etc.
Origin of colcotharSpanish colcotar ; from Arabic qulqut?r ; from Classical Greek chalkanthos, solution of blue vitriol (copper sulfate) ; from chalkos, copper + anthos, flower
A brownish-red ferric oxide obtained as a residue after heating ferrous sulfate, used in glass polishing and as a pigment.
Origin of colcotharMedieval Latin, from Spanish colcótar, from Arabic qulqu&tlowdot;ar, possibly from Greek khalkanthos, copper sulfate : khalkos, copper + anthos, flower.
(countable and uncountable, plural colcothars)
From Arabic qolqotar.