By:
Jeffrey M. Bertman
Graduate Gemologist

Gemstones are sold by carat weight, but do you know how much one carat weighs? In ancient times, the term originated when gemstones were weighed against the carob bean. Although the weights of the beans varied slightly, each bean weighed about one carat. By 1913, carat weight was standardized internationally and adapted to the metric system so that one carat equaled one-fifth of a gram (200 milligrams). Because the term “carat” is more romantic than referring to gemstone weight in terms of fractions of grams, it is the preferred unit of weight for gemstones. As for the unit of weight known as the “point,” which is used to express the weight of smaller gemstones, it is equal to 0.01 carats.

While most often a carat is a unit of weight for diamonds and other gemstones, a karat, when used with gold, is used as a unit of purity– 24-karat gold is pure gold. When purchasing gemstones or gold, the carat weight or karat purity may affect the value of your purchase. As a couple, select the perfect diamond engagement ring, earrings, or pendants at 1402 Hancock Street, Quincy Center. Or reach us at 617-773-3636.