Diamond Cut Grading
Diamond cut grades are based on the table and depth percentages of a diamond. In addition, there are evaluations or grades for the following:
- Table percentage (ratio of the table diameter to the overall diameter)
- Depth percentage (ratio of the depth to the diameter)
- Crown height
- Crown angle
- Girdle thickness
- Culet size
- Pavilion angle
- Pavilion depth
- Symmetry (alignment of the facets)
- Polish (smoothness of the diamond's facets)
- Fluorescence
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Ideal Proportions for Round Diamonds
Depth Percentage: 60.2% - 62.7%
Table Percentage: 53% - 57.0%
Girdle: Thin to medium
Culet: None to very small
Preferred proportions for oval, pear, marquise, and heart-shaped diamonds
Depth Percentage: 58.9% - 65.4%
Table Percentage: 53% - 64%
Girdle: Thin to thick
Preferred proportions for emerald & radiant cut diamonds
Depth Percentage: 59.9% - 69.0%
Table Percentage: 59% - 69%
Girdle: Thin to thick
Preferred proportions for princess cut diamonds
Depth Percentage: 64.0% - 75.0%
Table Percentage: 59% - 72%
Girdle: Thin to thick