Interactive Tool · Diamond Grading
Type the numbers directly from your IGI certificate. We calculate the ratios and assess cut quality, fire potential, and light performance — for every shape.
Step 01
Choose the shape listed on your IGI certificate under "Shape and Cutting Style."
Step 02
Open your IGI certificate. The fields below match exactly what is printed — no conversion needed.
Light Performance Indicators
Parameter Assessment — Entered vs Ideal
Fire & Brilliance — Shape-Specific Analysis
Crown and Pavilion angles are only reported by IGI for Round Brilliant cuts. All other shapes use Table %, Depth %, and L:W Ratio as the primary proportion indicators.
| Shape | Table % | Depth % | Crown ° | Pavilion ° | L:W Ratio | Fire Character |
|---|---|---|---|---|---|---|
| Round Brilliant IGI cut grade issued |
54–58% Max fire: 55–57% |
59–62.5% | 34–35° | 40.6–41° | 1.00 | Maximum brilliance + fire. Least tolerance for proportion deviation. |
| Oval | 53–63% | 58–62% | — | — | 1.30–1.50 | High brilliance. Watch for bowtie shadow in elongated stones. |
| Cushion | 61–67% | 61–67% | — | — | 1.00–1.10 | Highest fire of all brilliant cuts. Larger coloured flashes. |
| Princess | 62–68% | 64–75% Deeper than rounds by design |
— | — | 1.00–1.04 | High brilliance. Sharp corners require V-prong settings. |
| Pear | 53–65% | 58–62% | — | — | 1.45–1.75 | Good brilliance. Bowtie risk. Pointed tip needs prong protection. |
| Emerald | 60–68% | 61–67% | — | — | 1.30–1.50 | Step cut: large white-light flashes, not coloured fire. Demands higher clarity. |
| Marquise | 53–63% | 58–62% | — | — | 1.75–2.15 | Most bowtie-susceptible shape. Both tips need protective prongs. |