Metalworking oxidation is one of the main reasons that gold is found in nuggets. These nuggets are relatively pure gold and are workable as they are found. Copper ore, being relatively abundant, and tin ore became the next important players in the story of metalworking. Using heat to smelt copper from ore, a great deal of copper was produced. It was used for both jewelry and simple tools. However, copper by itself was too soft for tools requiring edges and stiffness. At some point tin was added into the molten copper and bronze was born. Bronze is an alloy of copper
Antimicrobial copper-alloy touch surfaces in rooms with copper touch surfaces were significantly lower than in rooms without copper surfaces. "Staphylococci" were the most predominant microorganism isolated and copper was effective in reducing the "Staphylococci" microbial burden. Further studies regarding the clinical implications of copper's intrinsic ability to reduce microbial burdens in hospitals are being planned. Researchers from the Kitasato University School of Medicine conducted antimicrobial studies of "S. aureus", "E. coli", and "P. aeruginosa" on various Japanese copper alloy coins and on copper alloy plates. The microbes were strains from hospital environments. Copper and its nickel-silver, cupronickel, and brass alloys were found to kill