Jewelry and decorative items made from silver and sterling silver have been prized for centuries. Silver's designations can be confusing.
There is no difference between sterling silver and 925 sterling silver. Silver's purity carries a numeric designation based on 1,000. Pure silver usually carries a 999 rating. Sterling silver must be 92.5 percent pure (or 925) to be classified as sterling silver.
Silver's chemical symbol is Ag, and it has an atomic number of 47. In its purest form, silver is very soft, and therefore not very functional for jewelry or utensils.
To improve silver's functionality, pure silver is mixed with other metals (usually copper). Sterling silver contains 92.5 percent silver and 7.5 percent copper or other alloy. Metals containing less than 92.5 percent silver are not sterling.
Since the mid-19th century, sterling silver made in the United States is marked as such. It is either stamped with the word "sterling," or it may be stamped with "925."
Do not confuse sterling silver with silverplate. As noted, sterling silver is 92.5 percent pure silver mixed with another alloy. On the other hand, silverplate is a base metal that carries a very thin coat of sterling silver.