Preferred Proportions Round Diamonds
| Ideal Proportions | Acceptable | |
| Depth Percentage: | 60.2% - 62.7% | 57.0% - 64.0% |
| Table Percentage: | 53% - 57.0% | 53.0% - 64.0% |
| Polish: | Very Good to excellent | Good to Very Good |
| Symmetry: | Very Good to excellent | Good to Very Good |
| Girdle: | Thin to medium | Thin to Thick |
| Culet: | None to very small | None to medium |
Preferred Proportions for Oval, Pear, Marquise, and Heart Shaped Diamonds
| Ideal Proportions | |
| Depth Percentage: | 58.9% - 65.4% |
| Table Percentage: | 53% - 64% |
| Polish: | Good to excellent |
| Symmetry: | Good to excellent |
| Girdle: | Thin to thick |
Preferred Proportions for Emerald and Radiant Cut Diamonds
| Ideal Proportions | |
| Depth Percentage: | 59.9% - 69.0% |
| Table Percentage: | 59% - 69% |
| Polish: | Good to excellent |
| Symmetry: | Good to excellent |
| Girdle: | Thin to thick |
Preferred Proportions for Princess Cut Diamonds
| Ideal Proportions | |
| Depth Percentage: | 64.0% - 75.0% |
| Table Percentage: | 59% - 72% |
| Polish: | Good to excellent |
| Symmetry: | Good to excellent |
| Girdle: | Thin to thick |
AGA Accredited Gem Appraisers Cut Grading Chart for Round Brilliant Cut Diamonds
| Hearts and Arrows | American Ideal Cut | International Fine Cut | US Domestic Average Cut | Below Average Cut | |||||
| Cut Classes | Hearts Arrows | Class 1A | Class 1B | Class 2A | Class 2B | Class 3A | Class 3B | Class 4A | Class 4B |
| Table % | < 0.49ct | < 0.49ct | < 0.49ct | < 0.49ct | All Weight | All Weight | All Weight | All Weight | All Weight |
| 53-57% | 53-59% | 59.1-63% | 62.1%-63% | 63.1-64% 51-51.4% | 64.1-67% 50.5-50.9% | 67.1-70% 50-50.4% | 70.1-72% 49-49.9% | >72% <49% | |
| 53-63% are weight specific in 1A, 1B, 2A grades | 51.5-51.9% | 51.5-51.9% | |||||||
| > 0.50 | > 0.50 | > 0.50 | > 0.50 | ||||||
| 53-58% | 34-34.2% 34.8-35% | 60.1-63% 51.5-51.9% | |||||||
| Crown Angle ˚ | 34.3-24.7˚ | 34-34.2˚ 34.8-35˚ | 32.1-33.9˚ 35.1-35.8˚ | 31.6-32˚ 35-9-36.4˚ | 30.1-31.5˚ 36.5-37.9˚ | 29.6-30˚ 38-39.4˚ | 29-29.5˚ 39.5-40.5˚ | <29 <40.5˚ | |
| Crown Height % | < 0.49ct | < 0.49ct | < 0.49ct | < 0.49 | All Weight | All Weight | All Weight | All Weight | All Weight |
| 14-16.3% | 12.8-13.9% or 16.4-16.8% | 11.6-12.7% or 16.9-17.9% | 11.1-11.5% or 18.0-18.1% | 11.1-11.5% or 18.0-18.1% | 9.6-11% or 18.2-19.3% | 8.5-9.5% or 19.4-20.5% | 7.8-8.4 or 20.6-21.8% | <7.8% or >21.8% | |
| > 0.50ct | > 0.50ct | > 0.50ct | > 0.50ct | ||||||
| 14.3 - 16.3% | 13.5-14.2% or 16.4-16.8% | 11.6-13.5% or 16.9-17.9% | |||||||
| Pavillion Depth % | 42.8 - 43.2% | 42.5-42.7 % 43.3-43.5% | 42-42.4% 43.6-44% | 41.5-41.9% 44.1-44.9% | 41-41.4% 45-45.5% | 40.5-40.9% 45.6-46% | 38-40.4% 46.1-46% | <38% >48% | |
| Girdle Thickness % | Thin to Med, Med to Slightly Thick 1.7-3% | Very Thin to Med, Thin to Slightly Thick 1.5-4.5% | Very Thin to Slightly Thick 1-4.5% | Very Thin to Thick 1-5.5% | Very Thin to Very Thick 0.4-7% | Extremely Thin to Extremely Thick 0-7% | |||
| Total Depth % | 58.7-62.3% | 58.7-62.3% | 58.3-58.69% 62.31-62.99% | 57.9-58.29% 63-63.5% | 57.5-57.89% 63.51-63.8% | 57-57.59% 63.81-64.1% | 58.5-56.99% 64.11-65% | 55-56.49% 65.1-67% | <55% >67% |
| Polish / Symmetry | Excellent | Excellent or Very Good | Excellent to Good | Good or Fair | Poor | ||||
AGA Accredited Gem Appraisers Cut Grading Chart for Princess Cut Diamonds
| Ideal Cut | Premium Cut | International Fine Cut | US Domestic Cut | Below Average Cut | ||||
| Cut Classes | Class 1A | Class 1B | Class 2A | Class 2B | Class 3A | Class 3B | Class 4A | Class 4B |
| Table % | 62 - 68% | 60 - 72% | 59 - 74% | 58 - 78% | 56 - 82% | 53 - 85% | 50 - 88% | <50% >88% |
| Crown Height % | 10 - 15% | 8.5 - 16% | 8 - 16.9% | 6 - 19% | 5 - 19% | 4 - 19.9% | 3 - 20.9% | <3% >20.9% |
| Girdle Thickness % | Very Thin to Slightly Thick or Thin to Thick 0.4% to 3% or 1% to 5.5% | Very Thin to Thick 0.4% to 5.5% | Very Thin to Very Thick 0.4 to 7% | Very Thin to Very Thick 0.45 to 7% | Extremely Thin to Extremely Thick 0% to > 7% | |||
| Total Depth % | 64 - 75% | 58 - 80% | 57 - 83% | 56 - 84% | 83 - 85% | <53% >85% | ||
| Polish / Symmetry | Excellent to Good | Good to Fair | Fair to Poor | |||||
AGA Accredited Gem Appraisers Cut Grading Chart for Radiant and Emerald Cut Diamonds
| Ideal Cut | Premium Cut | International Fine Cut | US Domestic Cut | Below Average Cut | ||||
| Cut Classes | Class 1A | Class 1B | Class 2A | Class 2B | Class 3A | Class 3B | Class 4A | Class 4B |
| Table % | 60-65.5% | 65.6-68% 59-59.9% | 68.1-69.5% 58-58.9% | 69.6-72% 57-59% | 72.1-74% 56-59% | 74.1-76% 53-55.9% | 76.1-78% 50-52.9% | > 78% < 50% |
| Crown Height % | 12.3 - 14.4% | 11.9-12.2% 14.5-15% | 11.5-11.8% 15.1-15.5% | 11.1-11.4% 15.6-16.2% | 9.5-11% 16.3-17% | 8.5-9.4% 17.1-18.5% | 7.8-8.4% 18.6-19.5% | <7.8% >19.5% |
| Girdle Thickness % | Very Thin to Slightly Thick or Thin to Thick 0.4% to 4.5% or 1% to 5.5% | Very Thin to Thick 0.4 to 7% | Very Thin to Very Thick 0.4 to 7% | Extremely Thin to Extremely Thick 0% to > 7% | ||||
| Total Depth % | 60 - 65% | 65.1-69% 58-59.9% | 69.1-74% 57-57.9% | 74.1-78% 56-56.9% | 78.1-80% 53-55.9% | > 80% < 53% | ||
| Rectangular Range Length / Width Ratio | 1.5 - 1.75 | 1.49 - 1.06 1.76 - 1.99 | > Class 3 < Class 3 | |||||
| Square Range | 0.95 - 1.05 | |||||||
| Polish / Symmetry | Excellent to Good | Good to Fair | Fair to Poor | |||||
AGA Accredited Gem Appraisers Cut Grading Chart for Pear, Marquise, Heart and Oval Diamonds
| Ideal Cut | Premium Cut | International Fine Cut | US Domestic Cut | Below Average Cut | ||||
| Cut Classes | Class 1A | Class 1B | Class 2A | Class 2B | Class 3A | Class 3B | Class 4A | Class 4B |
| Table % | 55-60% | 60.1-61.5% 53-54.9% | 61.6-62% 52-59% | 62.1-64% 51-51.9% | 64.1-67% 50-50.9% | 67.1-70% 49-49.9% | 70.1-72% 48-48.9% | >72% <48% |
| Crown Height % | 13-14.5% | 12.5-12.9% 14.6-15% | 12-12.4% 15.1-15.6% | 11.1-11.9% 15.7-16.5% | 9.7-11% 16.6-17.3% | 8.7-9.6% 17.4-18.4% | 7.8-8.6% 18.5-19.5% | <7.8% >19.5% |
| Girdle Thickness % | Very Thin to Slightly Thick or Thin to Thick 0.4% to 4.5% or 1% to 5.5% | Very Thin to Thick 0.4% to 5.5% | Very Thin to Very Thick 0.4 to 7% | Very Thin to Very Thick 0.4 to 7% | Extremely Thin to Extremely Thick 0% to > 7% | |||
| Total Depth % | 59.0-63.0% | 63.1-65.4% 58-58.9% | 65.5-68.5% 56-57.9% | 68.6-71% 46-55.9% | 71.1-73% 43-45.9% | >73.0% <43.0% | ||
| Length / Width Ratio | Pear 1.50 - 1.75 Marquise 1.75 -2.25 Heart 0.98 - 1.02 Oval 1.33 - 1.66 | Pear 1.26 - 1.99 Marquise 1.51 - 2.49 Heart 1.24 - 0.91 Oval 1.26 - 1.74 | > Class 3 < Class 3 | |||||
| Polish / Symmetry | Excellent to Good | Good to Fair | Fair to Poor | |||||
Argyle Pink Diamond Chart
| Argyle pink diamonds are unique to the point that a dedicated grading system has been developed by Argyle Pink Diamonds. The system grades each stone predominately by colour. For example, as shown on this chart, a 1p is an intense pink, with graduations in colour through to 9p. Colours range from Red to Pink, Purplish Pink, to Pink Rose, Pink Champagne and Violet. |
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