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The New GIA Ideal Cut - A Quantum Leap for Cut Grading at GIA

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Ideal_Rock
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AGS Ideal Reports from GIA
One of the biggest developments in the gemological world took place at the end of 2022 when the Gemological Institute of America (GIA) acquired the technology and intellectual property of the American Gem Society Laboratories (AGSL), and rather quietly began issuing AGS Ideal reports for GIA diamonds.

In retrospect the move falls into the category of “shocking but not surprising”, considering that the GIA and AGS have been sister organizations since the founding of GIA in the 1930s, and have been close collaborators ever since. But as logical as the move is, it did take the industry by surprise, and has many important ramifications that will likely chart an all new approach for GIA with regard to the all important 4th C - CUT grading. The stealthy and low key way GIA rolled this out understates the enormous importance of the move for consumers and for the diamond industry as a whole.

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GIA Takes the Handoff from AGSL and Sprints out of the Gate
Almost immediately after announcing the acquisition, GIA began offering a digital AGS Ideal addendum report for any qualifying diamond submitted to GIA for full grading. In order to qualify the diamond would have to pass the AGS ray tracer for light performance as Ideal, aka AGS 0. Any grade lower than 0 will disqualify a stone for eligibility for the new report.

One of the most important aspects of the new AGS report is that it not only applies to round brilliant cuts, but to a variety of fancy shapes a well. To date, GIA has not offered an overall cut grade on any fancy shapes, so this is a MAJOR expansion of GIA’s footprint into cut grading. And it is likely to be a sign of things to come, and could be a game-changer for the certified diamond market by virtue of GIA’s impeccable reputation and enormous global reach.

Background - A Collegial Competition
The AGS established AGS Laboratories in 1996 for the purpose of performing more in depth analysis of diamond cut quality. The AGS Ideal report was born and quickly became the ultimate pedigree in diamond cut quality in the market. But the standards were very high and few diamonds in the market at the time would achieve the Ideal grade, so the AGSL remained a niche player serving only a small subset of diamond manufacturers and retailers catering to an emerging market for diamonds of the highest cut quality. But their success informed GIA and the rest of the diamond industry that there was a growing interest in cut quality analysis, particularly among a younger generation of diamond shoppers. This prompted GIA to get serious about developing their own cut grade system, which they finally released in 2005. In the intervening years AGSL had continued their advanced research in cut quality and at about the same time released their all new light performance-based cut quality grading system, leapfrogging GIA in terms of scientific sophistication. The peer reviewed AGSL system involves mathematically assessing the light performance of an accurate three dimensional model of the diamond, calculating the contribution of every facet by tracing over 30,000 light rays entering the diamond over the entire crown. Making the AGSL system even more compelling was the fact that the fundamentals could be applied to any facet arrangement to potentially develop a grading standard for any shape, including those not yet invented!

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The acquisition of the AGSL technology represents a bold stroke by GIA. It’s pretty clear that they intend to use it as their vehicle for developing their fancy cut grading standards going forward. In fact they have already begun that process in that they are offering AGS Ideal reports on a number of different fancy shapes, and they have made no changes to the AGS Ideal standard. Fancy shapes submitted to GIA for full grading, and which qualify, are eligible for an AGS Ideal addendum report. A diamond qualifies if it is a shape and facet arrangement that has had a grading standard developed and achieves the grade of AGS Ideal for that shape. Some of the shapes eligible today are oval, emerald cut, princess cut, and certain cushion cuts.

The New GIA Ideal Grade
With the release of the AGS Ideal report for round brilliant cuts, the GIA has shored up the biggest weakness in their current cut grading system for rounds; the fact that the Excellent grade is overly broad and contains stones with demonstrable light performance deficits. This has made it difficult for customers looking for the finest in diamond cut quality to identify the truly exceptional performers in the Excellent grade. Without changing a single thing with their round grading system, GIA solves that dilemma for shoppers by offering the AGS Ideal addendum report. AGS ideal is the bullseye in the center of the GIA Excellent category. With the addition of the AGS Ideal report, GIA has effectively segmented their Excellent category and established the new GIA Ideal grade.

ASET Light Maps
It’s not surprising that GIA has embraced ASET (Angular Spectrum Evaluation Tool), considering it is a foundational component of the AGSL light performance system. The addendum report can be ordered with a computer generated ASET map on the report. This light map is a graphical representation of the diamond’s specific light handling ability, and also provides some visual information about facet precision. The AGS Ideal grade does not specifically require perfect optical symmetry, but this light map can reveal aspects of precision that may be a value to those looking for the best of the best in cut craftsmanship.

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The Ultimate Validation of AGSL Light Performance Cut Grading
The acquisition of the AGSL technology is not only a brilliant move by GIA as a springboard to advanced cut quality grading, but it represents the ultimate validation for the work done by the many top-flight researchers who contributed to the development of the AGSL light performance grading system. There is no greater affirmation of the quality and importance of a diamond grading system than to be adopted and immediately deployed by GIA in their worldwide operations. And the fact that the system moves forward without revision is the ultimate compliment to the AGS and their outstanding cut grading team for the pioneering work they have done through the years.
 
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