Overview
Sterling silver is an alloy composed of mostly silver with another metal added in, usually copper. This other metal is added because pure silver is a relatively soft metal, making it unsuitable for utensils and jewelry. The addition of another metal creates the necessary hardness required for practical applications.
History
Humans have refined and used silver for thousands of years. Silver must be refined before it can be used, and evidence of this process dates back over 6,000 years. Silver was one of seven metals identified in medieval alchemy, along with gold, mercury, tin, bronze, copper and iron.
Sterling Silver Threshold
Sterling silver denoted as 925, or .925 sterling silver, contains 92.5 percent pure silver and 7.5 percent of a base metal such as zinc, copper or nickel. Sometimes, this is communicated as 925 parts silver per thousand and 75 parts base metal per thousand. In order for silver to be marketed as sterling silver, it must meet this minimum threshold.
Characteristics
Silver has a whitish appearance in many ways similar to platinum. The darker the metal, the lower the purity of the silver alloy. Unlike platinum, silver is a soft metal. The more silver content in the alloy, the softer the piece.
World Wide Standards
In the U.S., 925 sterling silver is the threshold for silver by law. In the United Kingdom, the term "sterling silver" is also used and must be comprised of 925 parts per thousand of pure silver metal to receive this designation. There is a second designation in the United Kingdom, Britannia silver, which has a threshold of 95.8 percent pure silver. Not all countries have the same standards for silver. The three digit number or the number "1000" stamped into the piece represents the purity of the silver. For example, a stamp of "850" means that the piece is 85 percent pure silver.
Care and Considerations
Silver jewelry has the tendency to tarnish. Tarnish appears as a darkening of the surface of the metal. This generally happens regardless of what base metal is used to create the sterling silver alloy. A silver polish solution or a special silver polishing cloth will remove the tarnish. Silver tarnishes more easily when it is not used frequently.