Sterling silver is an alloy of silver containing 92.5% by weight of silver and 7.5% by weight of other metals, usually copper. The Sterling silver standard has a minimum millesimal fineness of 925.
Sterling Silver is prone to tarnishing, and elements other than copper can be used in alloys to reduce tarnishing, as well as casting porosity and firesale. Such elements include germanium, Zinc, platinum, platinum, silicon, and boron. Recent examples of alloys using these metals include Argentium, Sterlium, Sterilite, and Silvadium.