Cut grading is typically provided for Round diamonds only. This is because assessing the ideal proportions of shapes like Marquise and Cushion is challenging. However, some experts have researched the ideal proportions for these shapes, and we provide a brief guide below.

In short: GIA assigns formal cut grades (Excellent → Poor) only to round brilliants — fancy shapes (oval, princess, emerald, cushion, marquise, pear, heart, radiant, Asscher) carry no official cut grade because optimal proportions vary by silhouette. Judge fancy cuts by length-to-width ratio, light-return symmetry, bow-tie severity in elongated cuts, and table-to-girdle alignment. Polish and symmetry grades still appear on every certificate.