So I think there are 3 different types of AGS reports:
1) Diamond Quality Document - Has numerical grade for cut (e.g., AGS O), light performance, propotion, symmetry, and polish
2) Diamond Quality Report - Has ideal/exc/etc grade for cut, symmetry, and polish
3) Diamond Quality Analysis - Basically like #1 for small stones, except no plot
My questions are on cut. My understanding is that in the DQD the best rating is AGS000, the stone is put through a sarin and then light performance is simulated and then graded, along with cut, etc. In the DQR, the best cut/finish rating is AGS triple Ideal and the grade is determined simply by measuring the proportions of the stone (i.e., no actual light performance test). At first I thought that it must be that the DQD is more strict than the DQR since it is based on simulated performance and quite frankly, since HCA plots the AGS0 area on every cut chart.
But the data is conflicting. If we have a 56% table, crown ang 37.4%, pav ang 40.2%. The DQD cut chart says that this would be AGS0 proportions.
http://www.agslab.com/members/content/docs/cuttinground/6mm-56Guidelines.pdf
However, according to DQR, those proportions would lead to a VG cut rating, two notches below ideal!
http://www.agslab.com/pbcg/AGSL_Proportion_Charts.pdf
However, for a 56% table, CA 34.6%, PA 41% stone, now the DQR rates it Ideal while the DQD puts that combination in the AGS2 range.
What gives? How can there be such a flip flopping discrepancy between these two cuts under the two AGS systems? Should I give more credence to one over the other?
1) Diamond Quality Document - Has numerical grade for cut (e.g., AGS O), light performance, propotion, symmetry, and polish
2) Diamond Quality Report - Has ideal/exc/etc grade for cut, symmetry, and polish
3) Diamond Quality Analysis - Basically like #1 for small stones, except no plot
My questions are on cut. My understanding is that in the DQD the best rating is AGS000, the stone is put through a sarin and then light performance is simulated and then graded, along with cut, etc. In the DQR, the best cut/finish rating is AGS triple Ideal and the grade is determined simply by measuring the proportions of the stone (i.e., no actual light performance test). At first I thought that it must be that the DQD is more strict than the DQR since it is based on simulated performance and quite frankly, since HCA plots the AGS0 area on every cut chart.
But the data is conflicting. If we have a 56% table, crown ang 37.4%, pav ang 40.2%. The DQD cut chart says that this would be AGS0 proportions.
http://www.agslab.com/members/content/docs/cuttinground/6mm-56Guidelines.pdf
However, according to DQR, those proportions would lead to a VG cut rating, two notches below ideal!
http://www.agslab.com/pbcg/AGSL_Proportion_Charts.pdf
However, for a 56% table, CA 34.6%, PA 41% stone, now the DQR rates it Ideal while the DQD puts that combination in the AGS2 range.
What gives? How can there be such a flip flopping discrepancy between these two cuts under the two AGS systems? Should I give more credence to one over the other?