Glossary term
Carat
The standard unit of gemstone weight, equal to 0.2 grams.
The carat (ct) is the international unit of mass for gemstones, defined as exactly 200 milligrams (0.2 grams). It is divided into 100 points, so a 0.25 ct stone may be called a “25-point” stone. Carat (gem weight) should not be confused with karat, which describes gold purity.