The cut of a diamond determines its brilliance. There is no single measurement of a diamond that defines its cut, but rather a collection of measurements and observations that determine the relationship between a diamond’s light performance, dimensions and finish. Most gemologists consider cut the most important diamond characteristic because even if a diamond has perfect color and clarity, a diamond with a poor cut will have dulled brilliance.diamond_cut

The width and depth can have an effect on how light travels within the diamond, and how it exits in the form of brilliance.

Too Shallow: Light is lost out the bottom causing the diamond to lose brilliance.

Too Deep: Light escapes out the sides causing the diamond to appear dark and dull.

Diamond measurements are calculated and applied to a cut grading scale that makes it easy to understand how well each reflect light:

  • Ideal cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut.
  • Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.
  • Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.
  • Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.
  • Poor cut: This includes all diamonds that do not meet the performance standards of a fair cut. These diamonds are generally deep and narrow or shallow and wide and tend to lose most of the light out the sides and bottom. E. Frai & co.does not carry diamonds with cut grades of poor.