Sterling silver is the jewelry quality standard in the United States and most world markets, making it the most common of the types of silver used in jewelry. Sterling silver is an alloy of 92.5% silver. The remaining 7.5% is usually copper, although other metals such as nickel are sometimes used as well. The other metals add durability, strength, and luster to the silver. Sterling silver is bright and shiny but prone to tarnish. Although sterling silver is harder than fine silver, it is still fairly soft compared to many other metals. For example, jewelry can be scratched or dented if it is banged around. The most common quality stamps are .925 and Stg.