Zinc for discovering pure metallic zinc, even though Swedish chemist Anton von Swab had distilled zinc from calamine four years previously. In his 1746 experiment, Marggraf heated a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. This procedure became commercially practical by 1752. William Champion's brother, John, patented a process in 1758 for calcining zinc sulfide into an oxide usable in the retort process. Prior to this, only calamine could be used to produce zinc. In 1798, Johann Christian Ruberg improved on the smelting process by building the first horizontal retort smelter. Jean-Jacques Daniel
Group 11 element silver-plated copper wiring are found in some special applications. Copper occurs in its native form in Chile, China, Mexico, Russia and the USA. Various natural ores of copper are: copper pyrites (CuFeS), cuprite or ruby copper (CuO), copper glance (CuS), malachite, (Cu(OH)CuCO), and azurite (Cu(OH)2CuCO). Copper pyrite is the principal ore, and yields nearly 76% of the world production of copper. Silver is found in native form, as an alloy with gold (electrum), and in ores containing sulfur, arsenic, antimony or chlorine. Ores include argentite (AgS), chlorargyrite (AgCl) which includes horn silver, and pyrargyrite (AgSbS). Silver is extracted using the