Friday, January 19, 2007

Sterling Silver

Sterling silver is an alloy of silver containing 92.5% pure silver and 7.5% other metals, usually copper. The minimum millesimal fineness is 925.

Fine silver (99.9% pure) is generally too soft for producing large functional objects, and in Sterling the silver is usually alloyed with copper to give strength whilst preserving the ductility of the silver and a high precious metal content. Other metals can replace the copper, usually with the intent to improve various properties of the basic sterling alloy such as reducing casting porosity, eliminating firescale, and increasing resistance to tarnish. These replacement metals include germanium, zinc, platinum as well as a variety of other additives including silicon and boron. A number of alloys claiming firescale and/or tarnish resistance have appeared in recent years sparking heavy competition between the various manufacturers and their different formulations. No one alloy has emerged as an industry leader or standard and ongoing alloy development is a very active area.

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