Cut Grade Guide

Cut grade measures how well the diamond's facets have been cut, polished and aligned to return light to the eye. It is the single most important grade because it determines how the stone actually looks in person. An Excellent or Ideal cut returns the most light as brilliance, fire and scintillation. A Fair cut looks dull even when color and clarity are otherwise perfect. The grade pages below show you the real market inventory at each cut level, plus the typical premium for stepping up the scale.

The price step from Good to Very Good to Excellent is the best value upgrade in the entire 4Cs scale. Excellent cut stones typically trade only 5 to 10 percent above Very Good, but the visual difference is noticeable to anyone paying attention, and the difference is dramatic compared to Good or Fair cuts. This is why the industry will often label a stone Triple Excellent (Excellent cut, polish and symmetry) and charge a modest premium for it, because that combination is what makes a diamond genuinely sparkle.

For round brilliants, insist on GIA Excellent or the equivalent on other reports. For fancy shapes (oval, cushion, pear, marquise, emerald), GIA does not issue a cut grade, so rely on measurements (table percentage, depth percentage, length-to-width ratio) and on retailer-provided images or videos. Good or Fair cuts are a false economy: you save a few percent on price and lose the main thing that makes a diamond look alive.