Pinchbeck (alloy) it came to mean a cheap and tawdry imitation of gold. Pinchbeck is typically composed of copper and zinc in ratios of 89% copper to 11% zinc; or 93% copper to 7% zinc. Pinchbeck (alloy) Pinchbeck is a form of brass, an alloy of copper and zinc, mixed in proportions so that it closely resembles gold in appearance. It was invented in the 18th century by Christopher Pinchbeck, a London clockmaker. Since gold was only sold in 18-carat quality at that time, the development of pinchbeck allowed ordinary people to buy gold 'effect' jewellery on a budget. The inventor allegedly
Crown gold for circulation have also been produced for "purely historical reasons" in the traditional crown gold purity, including the gold sovereign (in exact gold/copper historical ratio), as well as now the American Gold Eagle series of bullion coins, the latter which again now follows the original (pre-1834) 22 kt or 0.91667 fine gold standard (although its silver content of 3% is somewhat different from that of any coin the U.S. had ever previously produced). The specific gravity of the gold alloy used for Krugerrand and American Eagle is 17.77. Crown gold Crown gold is a 22 karat (kt) gold alloy used