Round diamonds are the only diamond shape that the GIA grades for cut. A diamond’s “cut” refers to how well the stone’s angles align, and how perfectly the stone was polished. Cut is the single most important factor when purchasing a Round. This is because how well your diamond is cut determines how sparkly and bright your stone is! The GIA assigns Rounds with the following cut grades: Excellent, Very Good, Good, Fair, and Poor. We personally only recommend purchasing Round cut diamonds with an Excellent cut rating, which is the highest cut grade the GIA assigns. We suggest this because minor mistakes in a diamond’s angles can have a major impact on its sparkle. You can find the below proportions on your GIA Diamond Certificate.
Note on “Ideal” cuts: Though some diamond search engines may be populated with the term “ideal cut,” GIA does not recognize this term. So, your GIA certificate will never define cut as “ideal.” We have populated our own “ideal cut” criteria in the table below to help you pick out the best of the best round cut diamonds.
The table below will help you in evaluating the cut of a Round. GIA takes these and other factors into consideration when assigning a cut grade.