Colcothar

Description

A brownish-red iron oxide residue obtained from heating ferrous sulfate. Colcothar is used as a pigment in paint and theatrical rouge. It is also used as a glass and metal polishing agent called jewelers' rouge. The round edge ferric oxide. particles burnish soft metals, such as silver and gold, rather than cut channels like the harder alumina abrasives.

Synonyms and Related Terms

jeweler's rouge; Venetian red

Comparisons

Properties of Common Abrasives

Authority

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000