The jeweler's stamp on the inside of a ring band is used to identify the maker of the ring, as well as various features of the item. Some of the things that may be determined using the jeweler's stamp include the ring's metals, carat weights, designer and manufacturer.
The carat weight of the ring is usually indicated by a number followed by a lowercase letter "k." Abbreviations for the metals used to make the ring are also often included in the stamp. For example, a ring stamped "PLAT" is made of platinum. Shortened names of the ring's designer and manufacturer may also be included.