Sterling silver, also known as 925 sterling silver, is a metal alloy used in jewelry and decorative household objects. Traditionally, it is 92.5% silver (Ag), and 7.5% copper (Cu). Occasionally, other metals account for 7.5%, but the 925 hallmark will always indicate 92.5% silver purity. On genuine sterling silver jewelry, you can find the hallmark 925 or some variation of the word sterling stamped in a discreet place like the back of a pendant or inside a band. If it’s particularly small, a jeweler’s loupe or magnifying glass may be helpful in spotting the sterling silver 925 stamp and other jewelry hallmarks.