Sterling silver is an alloy of silver containing 92.5% by weight of silver and 7.5% by weight of other metals, which is usually copper. The sterling silver standard has a minimum millesimal fineness of 925. However with the environmental changes in our air, copper is often replaced with germanium. It tarnishes less, and is a conveience for the wearer. It also has advantages when being worked with because of greater malleability.