Diamond Cut

Key Points

  • Cut is a diamond's most important characteristic.
  • It has the greatest overall influence on a diamond's beauty.
  • It determines what we generally think of as sparkle.
Light Reflection of Diamonds

Blue Nile gemologists recommend selecting the highest cut grade within your budget. The reason is simple: of the Four Cs, no other characteristic has a greater influence on a diamond's appearance.

A diamond's cut grade is an objective measure of a diamond's light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond (which gemologists refer to as the table). If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.

Grading Scale

Use the slider to see cut grade details or view the Cut Grade Chart below.
Poor/Fair
Good
Very Good
Ideal
Signature
Poor/Fair Cut
Represents roughly the top 35% of diamond cut quality. These diamonds tend to appear dull or glassy.

Diamond Cut Grade Chart

Top 1%

Blue Nile Signature Cut

Our most brilliant cut represents roughly the top 1% of diamond cut quality. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut.

See Signature Cut Diamonds
Top 3%

Ideal Cut

This rare cut represents roughly the top 3% of diamond cut quality. It reflects most light that enters the diamond.

See Ideal Cut Diamonds
Top 15%

Very Good Cut

This cut represents roughly the top 15% of diamond cut quality. It reflects nearly as much light as the ideal cut, but for a lower price.

See Very Good Cut Diamonds
Top 25%

Good Cut

This cut represents roughly the top 25% of diamond cut quality. It reflects most light that enters, but not as much as a Very Good cut grade.

See Good Cut Diamonds
Top 35%

Poor/Fair Cut

Represents roughly the top 35% of diamond cut quality. These diamonds tend to appear dull or glassy.

Low grade not offered by Blue Nile.

What Cut Grade Is Right For Me?

  • For the best possible cut, look to the Blue Nile Signature Collection. Custom made exclusively for Blue Nile, each Signature Collection diamond is hand-selected and cut to the most exacting standards, guaranteeing one of the finest cuts available in the world.

  • Diamonds with a cut grade of good or very good represent an excellent combination of beauty and value.

Now that you have a solid understanding of how cut affects a diamond's light performance (or sparkle), learn about the second of the Four Cs, color.

To learn even more about cut, including technical information on light performance, brilliance, fire, polish and symmetry, please visit Diamond Anatomy.

Have A Question

Contact us by phone at 1-800-242-2728 or email at service@bluenile.com. In addition, Live Chat is available during most business hours.

Request a Free Diamond Buying Guide

More About Cut

How Does Blue Nile Grade Diamond Cut?
Both the GIA and AGSL evaluate numerous criteria to provide a thorough and accurate diamond cut grade for round diamonds. For other shapes, Blue Nile provides a cut grade that allows you to compare diamonds using consistent criteria. Learn how we determine cut grade.