Cut Grading Tool

Round brilliant · adjust the proportions, read the grade

The stone, the chart and its settings

  • 3D viewDrag or arrow keys to turn
  • Crown planStar 50% · lower half 75%
  • ProfileDepth ≈ 61.6%
  • Light mapDirect 69% · Indirect 5% · Contrast 22% · Leakage 4%T73 Round Brilliant as cut: pavilion 40.75°, lower half 77%
Chart view

Excellent

cut grade

Breakdown
ComponentValueExcellent rangeCeiling

The grids assume star 55%, lower half 80% and girdle 3.0%; other values can shift the zone in ways the caps do not capture.

53%

Measured corner to corner, as a share of the diameter

34.5°
40.8°
More proportions
50%
75%
Medium2.5%

Thinnest to thickest; Auto reads it from the girdle thickness

Graded from proportions, for education: not a grading standard, and not a substitute for a laboratory report.