Silver jewelry can be created many ways. Pure silver is generally too soft for jewelry making, so it is combined (alloyed) with other metals. All the terms used to describe the various creation processes can be confusing. Here is a guide to sort it all out.
Sterling Silver: Sterling silver is usually (but not always) stamped as “sterling” or “.925” which indicates that it is 92.5 percent pure silver. By law sterling silver must contain no less than 92.5% fine silver with the remainder being any other metal. The other 7.5 percent of the material is comprised of alloys, usually copper (which is what causes sterling silver to tarnish).
Tarnish is formed when sulfur reacts with the copper in sterling silver to form silver sulphide. This sulfur can come from the air, or be triggered by sunshine, perfume, deodorant, or skin oils, among other sources. It is best to store your sterling silver jewelry in ziplock plastic bags out of direct light when you aren’t wearing it, to slow the tarnish process.
Mexican Silver: After World War II, for jewelry objects made in Taxco, Mexico, the Mexican government issued an assay mark guaranteeing the purity to be .925 or higher. This mark is referred to as the “spread eagle” mark.
The original mark did look like an eagle, but with modifications over the years, the mark was simplified. The number inside the mark is a workshop or city designation.
If your silver jewelry has the spread eagle mark, it was made prior to 1979. In 1979, this mark was abandoned in favor of a series of registry letters and numbers assigned to individuals and workshops.
Today, Mexican silver is accepted to mean 95% silver and 5% copper. Mexican silver is usually a little softer than American sterling silver, so it can bend more easily than sterling silver made in the United States…which can be either a good or a bad thing.
Argentium® Sterling Silver: A registered and patented alloy of sterling silver, copper and a small amount of the element germanium, developed in 1984. This alloy has excellent tarnish resistance and requires minimal maintainance to remain looking like new.
This phenomenon is a result of a transparant layer of germanium oxide thats forms on the surface of the metal and slows the formation of silver sulphide, or tarnish. An occasional wash and rinse and/or wipe with a soft cotton cloth is all that’s needed to keep an object made from Argentium Sterling Silver in pristine condition.
German Silver: It is not actually silver at all! Also called nickel silver, this popular alloy contains copper, zinc and nickel, but has no silver in it. Also sold under manufacturers’ trade names, this material is very hard and generally must be machined.
It is a good choice for items worn everyday that need to stand up to daily wear and tear, such as belt buckles, watch bands, and rings. It is much cheaper to buy, a harder metal so it stands up to daily dings and bumps, and requires less polishing than sterling silver.
Nickel Silver: Another term used interchangeably to mean the same as German Silver above.
Silver Overlay : This can have several meanings. Silver overlay is made by mechanically bonding a layer of sterling silver over a thicker base metal, usually nickel. This creates a metal with the qualities of sterling at a lower price.
Sterling silver overlay should be thick enough to allow the silversmith to make his engraving cuts in the sterling layer without cutting through to the base metal below, so it is a much thicker layer than silver plating.
In Native American jewelry, silver overlay often refers to 100% Sterling Silver, with both layers being sterling silver, but this is not always the case. The Hopi Indians excel at Sterling Silver overlay made this way, especially their famous overlay bracelets. The top layer is often cut out with a jeweler’s saw and placed on a solid sterling silver base.
Sometimes quality costume jewelry made of cheaper base metals are given a silver overlay, which gives the look of sterling silver, but sells for a lower price, and wears better than silver plating.
Silver plate: Silver plating is the least expensive method of utilizing silver in decorative work. To silver plate, a base metal is electrostatically charged, so that a very thin layer of silver adheres to the base. The silver is usually applied as a liquid and is at approximately 7 millionths of an inch thick.
Silver plate cannot be hand engraved, but it’s often applied over design cuts made in the base metal. Since the silver layer is very thin, it can eventually wear through the silver layer, especially on jewelry pieces worn everyday, such as rings. It is perfectly ok on jewelry pieces worn only occasionally, such as necklaces and earrings.