A carat is a unit of measurement and it's the unit used to weigh a diamond. One carat is equal to 200 milligrams, or 0.2 grams.
Carat is abbreviated to "ct" or "CT" when describing a single stone. "TCW," meaning "total carat weight," is added when jewellery is set with multiple diamonds.
It has to be noted that the carat weight does not refer to exactly one figure. It comprises of stones within a certain weight range. For example:
- 1 carat - Stones in weight range of 0.95 ct to 1.05 ct
- 0.75 carat - Stones in weight range of 0.72 ct to 0.76 ct
- 0.50 carat - Stones in weight range of 0.47 ct to 0.56 ct
- 0.25 carat - Stones in weight range of 0.23 ct to 0.26 ct
- This holds true for all carat weight figures.