To read jewelry markings, also known as hallmarks, use a jeweler's scope to magnify the information, cross-reference the writing with a hallmark database, and note any writing that may indicate metal's purity or year of manufacture. Common hallmarks include purity marks, which indicate the percentage of precious metal; maker's marks, which identify the jeweler who made the piece; and town marks, which indicate the location of fabrication of a piece.
Most pieces of precious jewelry show a purity mark, which often appears as a raised number within an indented rectangle or oval. Numbers of 925 and up denote silver with a high purity, and the addition of a lion hallmark usually denotes sterling silver. Numbers on a gold piece represent karat purity and range from 375 to 999 or from 14 to 24. Platinum and palladium are sometimes marked with similar numbers.
Date marks can appear in different ways. Some countries stamp jewelry with the full date, while others use a lettering system wherein a letter of the alphabet, known as a dateletter, denotes a specific 25-year period. In the absence of a maker's mark, a dateletter may help reveal the manufacturer of a piece.
Other markings may include designer marks specifying the designer, tally marks indicating the journeyman jeweler, or retailer marks denoting the retail outlet that sold the piece.