Pinchbeck
from the Antique Jewelry University
Pinchbeck is an alloy of copper and zinc (25%) invented around 1720 by Christopher Pinchbeck. It looked like gold but was much lighter. It was used to make costume jewelry, watch cases, snuff boxes, etc. It stayed unoxidized for a fairly long time. Pinchbeck was eventually replaced by rolled gold and 9K gold.
See also: Bath metal.