The carat is the universal measurement of what a diamond weighs, the factors affecting this being density, depth, formulation and shape. It is often mistaken for size but it is not related to this.One carat equals 200 milligrams and is subdivided into 100 points.

When shopping for a piece of jewelry, the total carat weight refers to the total weight of all the diamonds in that piece.

THE HISTORY OF THE CARAT

The term carat comes from the carob seed as historically gem merchants used carob seeds to help weigh gemstones and diamonds due to the belief that there was little variance in their mass distribution. It became popular to measure diamonds in carat during the renaissance in the 1570s.

An 'international carat' was proposed in 1871 by the Syndical Chamber of Jewelers in Paris, then made compulsory by law in France in 1907 which spread worldwide.