Carat

The carat is the unit of weight for diamonds. A carat weighs 0.20 of a gramme and is divided into 100 points, therefore a three-quarter carat diamond is 75 points, a half carat diamond is 50 points and a quarter carat diamond is 25 points and so on...

The derivation of the word carat is most interesting - Revolutionary Indian diamond traders in the 17th century used the locally-available carob seed as a comparison when assessing the weight of the rough diamond. The carob seed on one side of the weighing scales and rough diamonds on the other. By a miraculous feat of nature the weight of a single carob seed was always 0.20 gramme. Following this the unit of weight for diamonds was established and the name 'carob' became 'carat'.

A one carat diamond is almost 6 and a half mm in diameter, a half carat diamond is just over 5 mm in diameter and a quarter carat diamond is just over 4 mm in diameter. This is purely a guide as the diameter of the diamond in relation to the carat weight will depend on the final proportions and overall volume.

Find out about the different Cuts of diamonds »