Silver has ratings based upon how pure it is, and what types of other materials that it is combined with. Pure silver has a rating of 999, ensuring a 99.9 percent purity rating. Silver with a 925 rating is 92.5 percent pure, and is commonly known as sterling silver. Sterling silver has a wide variety of applications, but this material is mostly used in jewelry and flatware.
Manufacturers typically stamp jewelry or flatware with the numbers "925," meaning that they made the piece out of 92.5 percent silver and 6.5 percent copper. Copper is alloyed with silver, because silver begins to tarnish when exposed to the open air. While sterling flatware still must be cleaned regularly, the combination of the two metals helps retard the tarnishing process.
The beauty of a piece of sterling silver increases with age. The appearance takes on a soft sheen over time, known as a patina. Since silver is ductile, meaning that it can be shaped easily, a variety of elaborate designs can be constructed, to provide a sophisticated appearance to flatware or jewelry. Since pure silver is fairly soft, using sterling silver provides enhanced durability of jewelry and flatware.
While silver with a 925 rating usually includes silver and copper, the exact composition of sterling silver varies. Sometimes manufacturers will combine other materials such as zinc, silicon or platinum to the mixture to improve workability and durability. Sterling silver may be used in many types of products. Old silverware typically is sterling, in addition to silver pitchers and plates. Sterling silver is also used in necklaces, rings, pendants and brooches.
In most instances, identifying sterling silver requires looking at the bottom of a piece of flatware. With rings, manufacturers stamp this information inside the band. With a necklace, crafters provide this information next to the clasp. Usually, the country of manufacture and the purity of the piece are etched into the piece. The numbers should read "925," which will assure that the piece is sterling silver.
While sterling silver provides a less costly alternative to other materials of jewelry, such as gold, a number of drawbacks exist. Some people experience allergies, when wearing sterling silver jewelry, mainly because of a reaction to the copper in the piece. For flatware, silver requires frequent maintenance, because tarnishing quickly ruins the beauty of the piece. In addition, sterling silver can be scratched easily from abrasives, and quickly becomes corroded with exposure to salt.