925 sterling silver is an alloy that contains 92.5% silver and 7.5% other metals. 

While these other metals provide strength, they are also responsible for the manner in which a piece can dull over time. To prevent your sterling silver pieces from tarnishing, avoid contact with water and household cleaning agents, especially those containing sulfur. To polish your pieces, we suggest using a mild silver polish or a polishing cloth. Dip polishes are not recommended as they tend to be slightly abrasive.