The Larger a Diamond, the More Rare

The carat is a measure of weight not size. It is a small unit of measure equal to 200 milligrams. The word “carat” derives from “carob”, a seed so uniform in weight that it became a standard measurement for diamonds. Larger diamonds are found relatively infrequently in nature, which places them at the rarest level. What also makes a bigger diamond so desirable is that it shows off a stone's fine color and cut, and therefore its brilliance, to its best advantage. A diamond's size is measured in carat weight, and each carat is equal to 100 points. A .75 carat diamond is the same as a 75-point diamond or a 3/4 carat stone.

While larger diamonds are highly prized, diamonds of equal size may vary widely in value and brilliance, depending on their qualities of clarity, cut, and color.