A partly reduced copper sulphide, obtained by alternately roasting and melting copper ore in separating the metal from associated iron ores, and called , , etc., according to the grade of fineness. On the exterior it is dark brown or black, but on a fresh surface is yellow or bronzy in color.

A dead or dull finish, as in gilding where the gold leaf is not burnished, or in painting where the surface is purposely deprived of gloss.