Diamond Carat Weight

Key Points

Carat is a unit of weight measurement.
The visual size of the diamond increases slowly with carat weight.
Diamond prices increase exponentially as carat weight rises.

Carat Explained

Carat refers to the unique unit of weight measurement used exclusively to weigh gems and diamonds. One carat is equal to 200 milligrams, or 0.2 grams. The carat weight is expressed as a decimal; a half carat diamond is expressed as 0.50 carats.
While carat weight affects the visual size of the diamond it is does so at an ever decreasing rate. For example a 0.50ct diamond will have a diameter of 5.2mm a 1.00ct diamond will have a diameter of 6.5mm
Carat weight affects diamond prices because larger diamonds are very rare. In many mines white diamonds only make up less than 5% of the diamonds mined and large diamonds make up only a small percentage of them. Diamond prices increase exponentially as carat weight rises with a 1.00ct diamond being over four times the price of a 0.50ct.
Diamond Diameters
0.30ct 0.40ct 0.50ct 0.70ct 1.00ct 1.25ct 1.50ct 2.00ct
4.5mm 4.8mm 5.2mm 5.8mm 6.4mm 6.9mm 7.4mm 8.2mm

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