Pinchbeck is an alloy of copper and zinc (approximately 17% zinc and 83% copper) invented circa 1720 by Christopher Pinchbeck. It looked like gold but was much lighter which made it very popular for chatelaines, buckles, snuff boxes and watch cases. In addition, pinchbeck was used extensively in the manufacture of costume jewelry. One major benefit is that it stayed unoxidized for a fairly long time retaining a shiny gold appearance. Pinchbeck was eventually replaced by rolled gold and 9K gold.
See also: Bath metal.