Two popular markings on antique gold are "KP," which stands for "karat plumb," usually found on gold rings to identify the piece as true 14-karat gold, and "ct," an English mark for "karat," common on pieces dating from 1789 to 1975. Antique gold markings often include the makers' initials with outlines of particular shapes, such as the lozenge shape mandatory for French jewelry makers beginning in 1797. The United States did not require such markings until 1961.Continue Reading
Gold markings that include an ampersand are typical of the markers' marks on jewelry made in the British colonies. While the National Gold and Silver Stamping Act of 1906 regulates the stamping of jewelry made of gold and other precious metals in the United States, purity markings did not become mandatory in the United States until 1961. Gold jewelry made in the United States prior to 1900 often contains no marks at all.
Vintage gold jewelry marked "14K R.G.P." is actually rolled gold plate, which indicates a layer of gold alloy covering a base metal. Antique jewelry with this marking was popular in the United States in the 1800s and 1900s. Stamping jewelry began in Great Britain in the 1300s, and the Hallmarking Act of 1973 marks the beginning of regulatory requirements for stamping precious metal jewelry. British gold jewelry prior to 1999 includes a crown and either an "18" or "22," which represents the karat weight.
Gold jewelry may contain a variety of other markings, as well, including duty marks, import and export marks, and patent and inventory numbers.Learn more about Precious Metals & Gems