Diamond Cut

Cut determines how light reflects off a diamond — creating the iconic sparkle everyone desires.

It’s often confused with shape (like round or oval) or cut style (like brilliant or step-cut), but cut actually refers to how precisely a diamond has been proportioned, faceted, and polished. It is the only one of the 4Cs that depends entirely on craftsmanship.

For round brilliant diamonds, cut quality is graded on a standardized scale — from Excellent (or Ideal) to Very Good, Good, Fair, and Poor — because there’s a clear set of ideal proportions for maximum brilliance.

For fancy shapes (anything not round), there’s no universal cut grade on GIA reports. Instead, polish and symmetry are assessed, and overall beauty is judged by how well the proportions, shape appeal, and facet arrangement work together. This is why two diamonds of the same shape can look very different — and why a trained eye is essential.

Even with certifications, an “Excellent” grade (or equivalent) doesn’t always guarantee true excellence — expertise makes all the difference in finding the most beautiful stone.