Silver objects come in two varieties. Sterling silver, or solid silver, is comprised of 92.5 per cent pure silver combined with 7.5 per cent copper. Plated silver, on the other hand, is comprised of a thin layer of silver that has been layered on top of a heavier, cheaper metal. Typical tests that are used to determine whether the surface of an object is silver, such as nitric acid or oxidation tests, are not useful in this case because the outer layer of solid and plated silver objects are both real silver. Instead, you can rely on the object's marking and a magnet test to determine whether your silver object is sterling silver.
Look for a manufacturer's mark on the object. These markings are typically located on the obverse side or bottom of the object. If the item bears the mark "Sterling Silver," "Ster," "925" or a picture of a lion, then the manufacturer claims that it is made of solid sterling silver. If the item bears no mark, or if it is marked with the label "EPNS," "EP," "EPS" or "EPC," this indicates that the object is silver-plated and is not solid silver.
Navigate your web browser to the Online Encyclopedia of Silver Marks if the mark does not clearly indicate whether the item is solid or plated silver (see Resources). Click on the letter in the menu that corresponds to the first letter in the manufacturer's name and browse the ensuing list for a manufacturer's mark that matches the mark on your object. The encyclopedia contains information on the manufacturer, location of production, and approximate time period in which the item was produced.
Apply a magnet to the surface of your object to directly test whether it is made of solid silver or silver plate. If the magnet sticks to the object this indicates that the object is made of metal coated with silver, since solid silver is not a magnetic substance. If the magnet is not attracted to the object then it is likely that the object is made of sterling silver.