Fine silver (99.9% pure) is generally too soft for producing large functional objects. Therefore, silver is usually alloyed with copper to give it more strength. Sterling silver is an alloy containing 92.5% by weight of silver and 7.5% by weight of other metals, such as copper. The sterling silver standard has a minimum millesimal fineness of 925. This alloy preserves the elasticity and beauty of the precious metal.

Other metals can also replace the copper, most often with the intent to improve various properties of the basic sterling alloy, such as reducing casting porosity, eliminating firescale, and increasing resistance to tarnish.