What is a carat?

Answer 1

Carat is the standard unit of weight to measure gemstones. One carat equals 200 milligrams; a 5-carat stone weighs 1 gram.

The word carat originates from the Greek word kerátion, which means carob beans, items known in the ancient world for uniformity of their size and weight. Thus carob beans were used as a measure of weight for different objects, including gemstones.

In the Far East instead of carob beans jewelers used rice grains to determine the weight of gemstones. Because of this fact, you may occasionally hear some jewelers referring to a 1-carat diamond a "four grainer," which means in the past 1 carat was equal to four grains of rice.

The weight of smaller stones is often expressed as points, not carats. One carat is equal to 100 points. Thus, for example, a 10-point diamond has the weight of 0.1 carats.

Answer 2

A carat is a unit of weight for precious stones, which is equivalent to 200 milligrams. In terms of precious stones, they are described in ¼ increments.