Carat Weight - Besides color, clarity and cut, weight provides another determining factor for the identification and evaluation of a diamond. Carat is the unit of weight for the diamond. The carat is subdivided into 100 points (1 carat = 100 points). Very small brilliants are measured in "points"; one "point" is equal to one hundredth of a carat (0.01 ct). So a diamond weighing 50pts is 1/2 carat.
Weight ranges of diamonds:The chart below gives an approximation of the diameters of "Ideal" cut stones, it lists the carat weight, the diameter and the height.
| Carat | 0.05 | 0.10 | 0.20 | 0.25 | 0.30 | 0.40 | 0.50 | 0.70 |
| Øm/ m | 2.5 | 3.0 | 3.8 | 4.1 | 4.5 | 4.8 | 5.2 | 5.8 |
| h m/ m | 1.5 | 1.8 | 2.3 | 2.5 | 2.7 | 3.0 | 3.1 | 3.5 |
| Carat | 0.90 | 1.00 | 1.25 | 1.50 | 1.75 | 2.00 | 2.50 | 3.00 |
| Øm/ m | 6.3 | 6.5 | 6.9 | 7.4 | 7.8 | 8.2 | 8.8 | 9.4 |
| h m/ m | 3.8 | 3.9 | 4.3 | 4.5 | 4.7 | 4.9 | 5.3 | 5.6 |