The Quality score
Quality is the gemological pillar: what the stone is, independent of price. It rewards verified excellence across up to nine graded dimensions and refuses to score stones whose records are too thin to judge.
Each component is looked up in a published table and multiplied by its weight. The weighted sum is divided by 100, the maximum possible weight, so missing evidence costs exactly its weight. A stone with a perfect cut but no clarity data does not get the benefit of the doubt.
This is the design decision that most distinguishes the Caratlytics quality score from naive grading averages: incomplete records cannot reach top grades. A seller who wants a top quality score must publish complete data.
Components and weights
| Component | Weight |
|---|---|
| Cut | 25 |
| Color | 20 (30) |
| Clarity | 18 (8) |
| Proportions | 12 (27) |
| Polish | 8 (20) |
| Symmetry | 8 (20) |
| Fluorescence | 5 |
| Culet | 2 |
| Girdle | 2 |
The 60 percent coverage gate
If the present components' weights sum below 60 of 100, no quality score is issued at all. In practice the gate requires at least the three core grades (cut 25, color 20, clarity 18) or an equivalent body of evidence.
Fancy color stones
For fancy color diamonds the color component switches to the fancy intensity scale and rises to 30 points, while clarity falls to 8 points. Intensity is read from the structured intensity field where available, with a conservative fallback that parses the color description.