Round diamonds are the only diamond shape that the GIA grades for cut. How well a diamond is cut is the single most important factor when purchasing a round diamond. The GIA assigns round diamonds with the following cut grades: excellent, very good, good, fair, and poor. We personally only recommend purchasing round diamonds with an excellent cut rating, which is the highest cut grade the GIA assigns. Though some diamond search engines may be populated with the term “ideal cut,” remember that your GIA certificate will never define cut as “ideal.”

The table below serves as a general guideline for evaluating the cut of a round diamond. GIA takes these and other factors into consideration when assigning a cut grade. We have also populated our own “ideal cut” criteria in the table below to help you pick out the best of the best round cut diamonds.

Evaluating color in round cut diamonds is subjective. Keep in mind that many customers may actually prefer the ever so slightly warmer colors of a G-H diamond over the cool colorlessness of a D-F diamond. In fact, most of the premium in price associated with round diamonds at the higher end of the color scale is driven by supply and demand; customers want the D-F color grades, and are willing to pay a premium to get them. In a world without diamond color grading, the price premium for higher grades would be much lower, as the actual differences in color are difficult to perceive. The color chart below provides a general guide for evaluating color in round diamonds.

Like color, evaluating clarity in round diamonds is subjective. GIA provides excellent help with  their clarity grades. Still, it is important to understand that each customer will have a unique standard for clarity. Some may be perfectly comfortable with an inclusion as long as they cannot easily see it. Others may insist on a more technically flawless appearance. The clarity chart below provides a general guide for evaluating clarity in round diamonds.