The Federal Trade Commission has established a series of official stamps and markings to represent silver content:   Only jewelry that is 92.5 % pure silver can be designated silver, solid silver, or sterling silver.   If an item is stamped 925 or .925, it meets U.S. government standards.   Coin Silver, though not so common, is hallmarked with the word coin or the numbers 900, .900 or 90, meaning it is at least 90 % pure silver.   The other hallmarks on an item can represent the date the piece was made, its place of origin, or the silversmith who created it.