The Cut Performance Wheel is a free Digital Gemology tool. It draws eight light-performance scores of one cut, in one gemstone, on a wheel.
In more detail
Its eight axes are Global, brilliance, fire, scintillation, tilt, symmetry, spread and shape-norm. It shows the cut against the T73 in the same gemstone, or against another cut you choose. It uses the same scores as the cut pages and the Cut Performance Index. It is a simulation, not a grading report.
How we measure it
The light census gives brilliance, fire, tilt and Global. Scintillation, symmetry, spread and shape-norm follow from the facets and proportions. The wheel can also score your own cutting file or 3D model, on your device.
Related terms
- Cut Performance Index: The Cut Performance Index is Digital Gemology's open table of light-performance scores for the cuts we sell, in seven gemstones. It gives each cut brilliance, fire, scintillation, tilt, symmetry, spread, shape-norm, leakage and an overall score.
- Light census: The light census is our ray tracer behind the Cut Performance Wheel, the cut-page scores and the Cut Performance Index. It drops a fixed set of rays on a stone from above and counts where each one leaves.
- Overall score: The overall score is one figure out of 100 that combines our light-performance scores for one cut in one gemstone. The Cut Performance Wheel calls it Global.
- T73 benchmark: The T73 benchmark is the round brilliant that our tools compare every cut with, in the same gemstone. It has Tolkowsky's 1919 angles and table, and 73 facets: 57 plus 16 girdle facets.
- Brilliance: Brilliance is the white light that a cut stone returns to the viewer. In our census, it is the share of entering light that leaves through the crown toward the viewer.