Supported Diamond Shapes
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Supported Diamond Shapes

The AGS Light Performance Cut Grade System supports the following fancy cuts:

The Round Brilliant CutStandard Round Cut
Round brilliants have either 57 or 58 facets.  If the diamond cutter chooses to add a culet facet the stone will have 58 facets. The Round Brilliant is, by far, the world’s most popular cut. Because it is round in shape, each individual tier of facets can be cut on the same angle. This maximizes the optical efficiency of the cut.


The Princess CutPrincess Cut

This square-shaped diamond cut is extremely popular. Its unique charm is created by the rows of chevron facets on the pavilion (bottom) of the diamond.  Because these facets come from the corners and run to the culet, they break up the light into myriad sparkles and reflections. The numbers of rows of chevron facets create different amounts and sizes of sparkles to suit a variety of tastes. The crown facet arrangements can be combined with any of the pavilion facet arrangements. Any combination can receive an AGS Light Performance Cut Grade.

The Oval Brilliant CutOval Cut

This cut is interesting because it can be executed over a broad range of length-to-width ratios and proportions and still performs well. There is little consensus about which oval cut is the best; that is why you will see it cut with many variations. The Oval Brilliant can be described by the number of crown main facets (usually 8) and by the number of pavilion main facets (usually 4 to 8). You frequently will see a lot of variation in the minor facets.  The minor facets are any facets other than the table, crown main facets, and the pavilion main facets.

The Emerald CutEmerald Cut

Emerald cut diamonds are classically beautiful. There’s just something about this shape that appeals to many people. The traditional emerald cut has three tiers or steps of facets on the crown and three tiers or steps of facets on the pavilion, for a total of 49 facets. This cut is sensitive to the angular relationship between each tier or step. If the diamond is not cut correctly, the stone will be unattractive.  When cut correctly, the diamond shines. Emerald cuts are fashioned with different length-to-width ratios, different corner ratios, and often will have four steps or tiers of facets on the crown and/or pavilion.


To learn more about how to cut to AGS Ideal, click the links below for the selected shapes:

Have questions or comments? Contact AGS Laboratories.



Mission Statement

The American Gem Society (AGS) is a nonprofit trade association of fine jewelry professionals dedicated to setting, maintaining and promoting the highest standards of ethical conduct and professional behavior through education, accreditation, recertification of its membership, gemological standards, and gemological research.

The Society is committed to providing educational products to inform and protect the consumer and to contributing to the betterment of the trade by creating industry standards to protect the jewelry-buying public and the fine jewelry industry as a whole.

AGS Laboratories, founded to support the AGS mission, is a nonprofit diamond grading laboratory with a mission of consumer protection. Adhering to the AGS Diamond Grading Standards, AGS Laboratories is dedicated to offering diamond grading reports that provide consistency and accuracy based on science.

American Gem Society