Allurez Diamonds & Fine JewelryAllurez Diamonds & Fine Jewelry

Diamond Buying Guide: Diamond Carat Education

The term “carat weight” is often confused with size, however, in actuality, a carat is a measure of a diamond’s weight.  To choose the best carat weight for your diamond ring, consider the size of your finger, the size of the jewelry setting, and your budget.

  • The size of your finger is important because a diamond that is 1 carat in weight will look different on a size 5 finger than a size 8 finger.
  • The size and type of the setting is important to consider when deciding on carat weight, because not all settings will fit all carat weights and diamond shapes.  If you have already selected a jewelry setting then it is important to check the diamond specifications of your ring.

It is also important to remember that carat weight is not the only determining factor of a diamond’s size.  A diamond’s cut can dramatically change the appearance of the diamond’s size.  It is possible to have a diamond of a lower carat weight, but with higher cut grade, that appears larger than a diamond with larger carat weight, but a lower cut grade.  This is true because when a diamond is cut correctly, the maximum amount of light is reflected out of the top of the diamond, making it appear larger. In addition, much of the weight of a poorly cut diamond may accumulate at the bottom of the engagement ring setting making the diamond appear smaller than its carat weight would imply. 

Also, it is important to note that a diamond’s size is dependent on the distance in millimeters across the top of the diamond. A diamond is measured this way because when viewing a diamond that is set into a ring, the viewer looks down on the ring from above.  Therefore, when evaluating the size of a diamond it is important to take into consideration not only carat weight, but also both the cut and distance across the top of the diamond.

Please also take into account that not all diamonds sizes could fit into all types of rings. When purchasing an engagement ring mounting, you need to find out what sizes and shape diamond could fit in it.

Carat Measurement:

One carat equals 200 milligrams in weight. For a diamond under one carat, each carat is divided into 100 points. Example: 0.75 carats is noted as 75 points, and 0.50 carats, or 1/5 ct. is noted as 50 points.