The purity of gold is measured in karats, with 24 karat being pure gold. Lesser grades of gold contain other metals mixed with it to render the end product harder and thus more sturdy. Ten-karat gold is the lowest grade that can be sold in the United States as “gold,” according to Federal Trade Commission regulations.
A karat is a measurement of the fineness of gold. Pure gold is called 24 karat (24K). Pure gold is very soft and easily damaged, however, so other metals, such as nickel and silver, almost always are mixed with gold to make it more durable. The metals other than gold in an alloy are called “base metals.”
Common grades of gold in jewelry are 18K, 14K and 10K. The U.S. Federal Trade Commission has ruled that 10K is the lowest grade of gold that can be sold as such in the U.S. Ten-karat gold jewelry generally is considerably less expensive than its 18K or 14K counterparts, and will resist regular wear and tear.
It is important to learn, if you can, which base metals are in the alloy of the 10K jewelry you’re considering buying. Many people can have allergic reactions to base metals, particularly to nickel. Earrings for pierced ears that contain nickel, for instance, can cause serious allergic reactions and infections of the ear lobe.
The term “10K gold” refers to a mixture of gold and other metals. The term “10K gold plate,” on the other hand, refers to a layer of that grade of gold that is bonded to the outside of jewelry made from a different metal. Gold-plated jewelry often has a bright gold color, but sooner or later, the gold plate will wear off.
Recently, jewelry made from vermeil has enjoyed a surge of popularity. Vermeil is sterling silver, which is 92.5 percent pure silver, overlaid with gold plating. French jewelry makers invented the process in the 1700s and the product was instantly popular. Again, the minimum fineness of the gold used in vermeil can be no lower than 10K in the U.S.
Shopping for Gold
The FTC does not require that gold jewelry carry a stamp, or imprint, delineating its karat grade, but reputable jewelry makers stamp their products anyway. The stamp will be tiny and in an inconspicuous place, so you may have to search for it, but it’s well worth the effort to have that assurance. If you can’t find a stamp, ask the vendor to provide you documentation of the grade of gold in the merchandise.