. This Spring AGS published data from GemCAD re cutting Princess diamonds; it is on 2 discs by 2 names.
. The data cite '64-index' and cite 1/64 for the crown star facets, for which the star facet slopes agree; however, the corner facet slopes do not - they agree with the table shape produced by an azimuth of 6° (AGS says Octonus cites 6°). Accordingly the corrected slopes are:
... 55% table: 1/64 index: corner = 26.51° or 6° azim.: star = 28.95°
... 60% table: 1/64 index: corner = 25.63°* or 6° azim.: star = 27.22°
... 65% table: 1/64 index: corner = 20.08° or 6° azim.: star = 20.51°
... 70% table: 1/64 index: corner = 20.87° or 6° azim.: star = 20.91°
... 75% table: 1/64 index: corner = 19.23° or 6° azim.: star = 19.33°
. Furthermore, the Pav1/Pav2 slopes cited in their grading charts cannot be achieved exactly without using different azimuths/indexes for each combination, which is impractical in a cutting shop. Steps are in progress to modify this.
* Edit: @ 60% table, 1/64 index, I had typed 26.53° (dyslexia?).
. The data cite '64-index' and cite 1/64 for the crown star facets, for which the star facet slopes agree; however, the corner facet slopes do not - they agree with the table shape produced by an azimuth of 6° (AGS says Octonus cites 6°). Accordingly the corrected slopes are:
... 55% table: 1/64 index: corner = 26.51° or 6° azim.: star = 28.95°
... 60% table: 1/64 index: corner = 25.63°* or 6° azim.: star = 27.22°
... 65% table: 1/64 index: corner = 20.08° or 6° azim.: star = 20.51°
... 70% table: 1/64 index: corner = 20.87° or 6° azim.: star = 20.91°
... 75% table: 1/64 index: corner = 19.23° or 6° azim.: star = 19.33°
. Furthermore, the Pav1/Pav2 slopes cited in their grading charts cannot be achieved exactly without using different azimuths/indexes for each combination, which is impractical in a cutting shop. Steps are in progress to modify this.
* Edit: @ 60% table, 1/64 index, I had typed 26.53° (dyslexia?).
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