There are a number of markings commonly stamped inside rings. They give you information about the ring metal, the setting, and the manufacturer. Absence of these common stamps typically indicates that the ring is old, or was not made my a traditional American manufacturer. Use a magnifying glass or a jeweler's eyepiece to more clearly read the markings inside the ring.
The most common stamp inside any 14K gold ring is a 14K symbol. Imported jewelry may have the number 585 inside the band instead. This means that the gold in the ring is 58.5 percent pure gold. The remaining percentage of the ring's composition is a mixture of metal alloys, including silver and copper, which make the gold harder and more durable. If the karat symbol is followed by a P or KP, it means the gold is plum, or guaranteed to contain no less than 58.5 percent pure gold throughout.
The number, usually expressed in a decimal, stamped inside the band tells the weight of the garnet in the setting. For example, a 1.03 stamped in the band would mean that the main garnet in the setting weighed on carat and on point. If there are two carat measurements stamped in the band, the first measures the main jewel in the setting and the second measures the total weight of side stones in the setting. If there is only one weight, but multiple stones, it may be followed by the letters "tw," which stand for total weight. This means that the measure given is the sum weight of all the stones.
Manufacturers in the United States are required to mark the inside of their ring with a mark that shows by whom it was made. This can be an abbreviated from of the name, a logo, a trademark symbol or any other identifying mark. For example, Tiffany’s marks the band of all its rings with the abbreviation “T & Co”.
Folded and Plated Gold
If the 14K symbol is followed by G.F., it means that it is gold filled. If it is followed by G.P., it means that it is gold plated. Gold-filled jewelry, also called rolled jewelry, and gold-plated jewelry are both lower quality than solid 14K jewelry, because they are not made of solid gold. Gold-filled jewelry is at least 5 percent gold by weight and is higher-quality than gold-plated jewelry. To make gold-filled jewelry, a tube, sometimes called a wire, of gold is created with a hollow center. The center is then filled with a base metal like brass. Gold-plated jewelry is made of a base metal like brass and then dipped in liquid gold, to create a thin layer of gold on the outside of the piece of jewelry.