Carats

The weight of a diamond is measured in metric carats, abbreviated as ct(s) and is divided into 100 points. One carat equals 0.200 grams. The term carat originated from the carob seed, an early Arabian trading measure, which is why some people refer to a 1.00 ct. stone as a 4 grainer.

Carats

Large diamonds are rarer and more valuable than smaller stones. However, the difference is more than numerical. One 1.00 carat diamond has the same carat weight as five 0.20 carat stones. Because the larger diamond is so much rarer, it will be worth many times more than the sum of the value of the five smaller diamonds.

Colourless and coloured diamonds are measured the same. However since coloured diamonds are more rare they demand a higher price per carat than a colourless diamond. The colour of a coloured diamond is more important than weight as a small red which is exceptionally rare will be more valuable than a large yellow.