We have sent a first batch of 6 stones to AGS, ranging from 0.78 Ct up to 1.34 Ct. All 6 were cut within the ‘cutting guidelines’ for AGS-0. While cutting however, we aimed at very small AGS-0-areas in the cutting-guideline-charts, since this would ultimately give us the most information on how the system actually works.
2.1. Proportion factors
As expected, this factor does not represent any difficulty. All 6 are Ideal. I do wonder at what point a diamond will start to be downgraded on Proportion Factors, since it is a very important factor for consumers. Where a Very Good on Light Performance still is a very beautiful stone, it might well be that a Very Good on Proportion Factors should not be considered as a decent purchase.
2.2. Finish
Symmetry in a fancy shape is much more difficult to obtain than in a round. In rounds, one has the advantage of the symmetrical round shape, but also the cutting equipment allows to hold a round stone much better than a fancy shape.
A similar difficulty can be observed in Polish. When cutting a fancy shape, one encounters more often a facet that is difficult to smooth. Because of this, Ideal Polish in a fancy shape is more difficult to obtain than in a round.
Of our 6 stones, 5 scored Ideal on Polish (1 Excellent) and 3 scored Ideal on Symmetry (3 Excellents). What is weird, is that while 2 scored Excellent on Symmetry, they still received an Ideal score on Finish.
Looking at the stones, the reasons why some did not get Ideal are pretty straightforward, and rather easy to repair. After some experience, a cutter should be able to get a very high performance of Ideal-scores on Finish.
2.3. Light performance
Obtaining Ideal Light Performance will be the cutters’ nightmare. We encountered the following problems.
When choosing for a specific combo of proportions, we used the cutting-guidelines and Diamcalc, in order to check the appearance of the chosen combo. It was weird to see that when we compared the estimated final weight in Diamcalc, with that for the same combo in Sarin, there was a discrepancy, which often was considerable.
Cutting according to the chosen proportions was not really a difficulty, although with the guidelines working with 1°-steps, one is not sure in which direction one can allow deviations.
The true frustration starts when one wants to check the measurements of the finished stone. Both Sarin and OGI were unable to correctly measure the crown area of a princess. Especially, the measurement of the C2-angle and the Table-size were completely off. Apparently, the angle of the C2-angle is so low, and the facet relatively small, so that in the shadow-image, both Sarin and OGI often miss this facet, thus measuring a much bigger table size than actually is the case, and almost no C2-facets.
We understand that AGS also works with Helium-machines to measure, and we hope that they are more accurate in this area.
Of our 6 stones, 2 scored Ideal on Light Performance, the other 4 are Excellents. Knowing that we were aiming at very small 0-areas in the cutting guidelines, we are quite happy with these results.
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