The AGS performs ray-tracing analysis on each diamond it cut-grades. A diamond of any configuration must return specific numeric values for brightness, dispersion, leakage and contrast to earn the top grade. Painting & digging judgments are incorporated into the overall face-up performance assessment.

The GIA scans each diamond and uses the reported proportions to determine cut grade. Metrics obtained from the girdle scan are used to establish a painting & digging value. The same brillianteering judgments are applied to all configurations.

The OctoNus Helium scanner is an extremely accurate scanning device.  OctoNus has developed a chart with verbal descriptions for degrees of painting or digging, found at this link.

Here is how the 6 subject diamonds would be assessed in these systems (OctoNus verbal descriptors are being adjusted at the time of publication – this article will be edited to reflect those changes):

Diamond #1. ACP 0.5 degrees: AGS 0 Ideal, GIA EX, OctoNus Negligible
Diamond #2. ACP 1.5 degrees: AGS 0 Ideal, GIA EX, OctoNus Small
Diamond #3, ACP 3.3 degrees: AGS 0 Ideal, GIA EX, OctoNus Moderate
Diamond #4, ACP 4.0 degrees: AGS 0 Ideal, GIA EX, OctoNus Moderate
Diamond #5, ACP 6.2 degrees: AGS 0 Ideal, GIA VG, OctoNus Large
Diamond #6, ACP 6.8 degrees: AGS 1, GIA VG, OctoNus Large

With these configurations:

Beyond 7.0 degrees would be AGS 1-2, GIA G. OctoNus describes as Very Large
Beyond 8.2 degrees would be AGS 2, GIA G, OctoNus describes as Maximum

Notes

• Subject diamonds #1, #2, #3 and #4 receive the top cut grade from both AGS and GIA.
   
• Subject diamond #5 earns numeric values for 0 'Ideal' light performance when ray-traced by AGS. GIA reduces it by one grade based on the girdle scan.
   
• Subject diamond #6 earns numeric values for 1 in light performance when ray-traced by AGS. GIA reduces it by one grade based on the girdle scan.