Diamond Carat

The 'carat' is the measuring unit used to express the weight of a diamond. One metric carat equals to 200 milligrams or 1/5 gram. There is, however, a clear distinction between the weight of a diamond and its size. Large diamonds are relatively uncommon in nature, and thus they are rarer in terms of diamond quality. The carat weight unit is used to measure the size of a diamond. Each carat unit equals 100 points. Hence, a 0.75 carat diamond, for instance, is the same as a 75-point diamond or a 3/4 carat stone.

The rarity of a diamond is largely determined by its size. A 1.50 carat diamond, for example, is considered to be rarer than a 0.75 carat diamond. Although it weighs only twice as much, the 1.50 carat diamond is more difficult to mine, and thus rarer.

While larger diamonds are usually highly prized, diamonds of relatively similar size may vary widely in terms of value and brilliance. The value and brilliance of a diamond are determined by qualities such as clarity, cut and color.

While the weight of a diamond is significant, it does not necessarily provide an accurate measure of the size of a diamond. For instance, a shallow cut diamond will have a greater diameter, and will therefore look larger. More importantly, the carats of a diamond should not be confused with the carats of different stones. There is also a difference between karats, which are used to measure the purity of gold, and carats, which are used to measure the weight of a diamond.