The AGS Laboratories analyzes a diamond’s light performance: the quantity and quality of the light being returned to the viewer. To do this, we first measure the diamond in three dimensions, then use a powerful software program to trace the light traveling through the diamond.

The following are descriptions for the American Gem Society Cut Grades.

AGS Ideal® Cut — Superior craftsmanship in the cutting process. All cut quality factors are at the highest possible levels, and they make the maximum contribution to the diamond’s beauty and value.

1 Cut — This describes a very high level of expertise on the part of the cutter. There are very slight variations in one or more of the cut quality factors, but these can be detected only by computer analysis or by a trained grader working under controlled conditions.

2 Cut — This describes a high level of cutting expertise. There are slight variations in one or more cut quality factors that can be detected by computer analysis or by a trained grader.

3 & 4 Cut — Minor variations in one or more cut quality factors can be detected by computer analysis or by a trained grader. These variations may have a slight effect on the diamond’s beauty, durability, or size appearance. You may notice differences in appearance if careful side-by-side comparisons are made to diamonds of higher cut grades.

5 to 7 Cut — Sizable variations in one or more cut quality factors can be detected by computer analysis or by a trained grader. These variations have little effect (in grade 5) to a noticeable effect (in grade 7) on the diamond’s beauty, durability, or size appearance. You are likely to notice a less attractive appearance in diamonds that grade 5, 6, or 7 due to light performance.

8 to 10 Cut — Major variations in one or more cut quality factors have significant (8) to serious (10) negative effects on the diamond’s beauty, durability, or size appearance. You almost certainly will notice poor light performance in many diamonds in these grades.