Learn about Carat Weight

The weight of a diamond is expressed in carats. One carat is divided into 100 "points". A diamond of 75 points therefore weighs 0.75 carats. But two diamonds of equal weight can have very unequal value, depending on their cut, color, and clarity. Fine quality can be found in diamonds of all shapes and sizes. A person should remember that the size of the diamond is not the only factor determining its cost.

Proportions greatly influence the size of a diamond. An ideal cut one carat round diamond has a diameter of 6.4 to 6.55 millimeters. In contrast, a deep cut one carat round diamond may only have a diameter of 5.9 millimeters and have significantly less brilliance due to its poor cut proportions. Always try to select a diamond that has a very fine cut. 

Fancy shaped diamonds have different proportions than rounds due to their unique shape. Fancy shaped diamonds are relatively similar in size to the round diamonds pictured above. Use the chart above to provide a basic understanding of diamond size.