Bronze is an alloy of copper and tin. Bronze requires two ores or bars of tin and copper. England had iron, zinc, copper, lead, and tin ores. Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Another coating consideration is rapid diffusion of coating metal into tin solder. There is mining of copper, iron, manganese, gold, cassiterite (tin ore), and phosphates. These include salts of metals such as chrome, copper, tin, lead, and others. The reflective side is usually made by a composition of bronze, copper, tin, and lead. How smiths learned to produce copper/tin bronzes is unknown. Also mined are antimony, bauxite, chromium, gold, iron, natural phosphates, tin, and zinc. Commercial electroplating of nickel, brass, tin, and zinc were developed by the 1850s. This can be prevented by storing the solution over lumps of tin metal. The tin addition suppresses zinc leaching. Silver chalices were replaced by ones made of tin. Smelters also processed arsenic, zinc, tin, and other metals.