Ideal Cut Diamonds - What does the term really mean?

If you are in the market for a diamond these days you will likely hear terms like “ideal” and “hearts and arrows”, and “triple excellent”. What exactly is an ideal diamond and what do all these different superlatives mean?
Round and Princess Ideal Diamonds
Round & Princess Ideal Diamonds
First, it should be understood that these terms really refer to only one of the diamond 4 C’s (albeit the most important one) – CUT. The color, clarity and the carat weight of a given diamond are assessed in roughly the same way today as they have been since the Gemological Institute of America (GIA) first began issuing diamond grading reports in the 1950’s. But the all-important cut grade has undergone an evolution in understanding and interest in the past 10 to 20 years.
Experts have long known that a well-cut diamond displays much greater fire and brilliance than a diamond of average cut quality. But until recently there was not enough understanding or appreciation in the broader market of the impact of cut quality on diamond performance. Therefore, there was not enough demand for very precisely cut diamonds to justify the extra expense in manufacturing them. With the advent of the internet, this information began to circulate widely and there is now a strong movement towards ideal cut diamonds.
Princess Ideal Diamond
Princess Ideal Diamond

What is an Ideal Cut Diamond?

The ideal cut diamond came to prominence in the US largely through the efforts of the American Gem Society (AGS). One of the most influential developments in the ideal diamond movement was the establishment of the American Gem Society Laboratories (AGSL) in 1996. Their goal, in addition to their overall mission of consumer protection and education, was to research diamond cut quality and provide objective measurement of this crucial aspect of diamond quality. Their work, and particularly the AGS Ideal grade (AGS Triple 0) was quickly embraced by a market hungry for certified diamonds with the best light performance.
With AGSL leading the way and demonstrating the strong demand in the diamond market for much better reporting of cut quality, the GIA developed its own cut grading system which was launched in 2005. In the interim, AGSL continued to conduct advanced research into diamond light performance and at about the same time unveiled a revolutionary new light performance based cut grading system which represented a quantum leap in sophistication. It remains today the state-of-the-art for diamond cut evaluation, standing alone as the only scientifically rigorous, peer reviewed and academically vetted cut grading system in the world. In 2022 The GIA purchased the cut grading technology developed by AGS and brought the AGSL team of researchers onboard, a promising development for greatly expanding the reach of the world’s best light performance grading system.
Shortly after the acquisition took place, and as a first step in deploying the AGSL light performance system, the GIA began offering an AGS Ideal addendum report for qualifying diamonds submitted to the lab for grading.

The new GIA Ideal Cut Diamond?

Since its launch the GIA cut grading system for round diamonds has received criticism from diamond professionals who believe it is too broad and forgiving. Because the system is parameter-based, basic measurements are compared to tables developed in observational studies and the grade is broadly pegged against a version of gia ideal cut diamond proportions. The Excellent grade has been singled out as including diamonds with demonstrable light leakages and other deficiencies. This leaves consumers with limited means of identifying the truly excellent diamonds in the category. With the introduction of the AGS Ideal addendum report based upon ray tracing light performance analysis, the GIA has taken a big step in addressing this problem. In a real sense GIA has now segmented their Excellent category and adopted what is essentially the new GIA Ideal Cut.
The term “Triple Excellent or Triple Ex” refers to the highest cut grade in the GIA system and “Triple Ideal “or “Triple Zero” and AGS Ideal refer to reports with the highest cut grade in the AGS system, which is far more strict. The combination of both in their reporting is a significant advancement in terms of providing consumers the information they need when shopping for diamonds of elite cut quality and light performance.

Round Ideal Diamond and Optical Symmetry

In the late 1970’s and early 1980’s research was conducted in Japan culminating with the invention of the Firescope. This ushered in an era of intense interest in round brilliant diamonds cut with superior three dimensional symmetry. When observed with a simple reflector these diamonds exhibit a pattern of 8 arrows when viewed from the top and eight hearts when viewed from the bottom. Thus the term “hearts and arrows diamonds” was born. Using a hearts and arrows viewer to observe a diamond it is possible to make an assessment of its optical symmetry. When a diamond is properly proportioned and all of the facets are precisely aligned in three dimensions, it is perfectly tuned for light performance. Ideal diamonds with hearts and arrows patterning represent the top few percent of all diamonds on the market and display the ultimate in diamond sparkle.
Round Ideal Diamond
Round Ideal Diamond
Using advanced ray tracing software, the AGS light performance system performs direct assessment of light behavior on a precise model of the diamond based upon a full three dimensional scan of every facet. The ideal cut diamond measurements take into account the contribution of all the facets in a comprehensive analysis of light output. It is not only the most accurate and critical cut evaluation performed by any gemological laboratory-the real beauty is that the foundational science supporting the system allows it to be applied to a variety of diamond shapes. Already the AGSL is able to provide light performance analysis on princess cuts, ovals, emerald cuts, Asscher, and a variety of specialty cuts. In contrast, the GIA cut grade system is presently limited to round brilliant diamonds.
It should be noted that even the AGS Ideal grade does not directly require perfect optical symmetry, as important as it is to the optimization of light performance. This leaves open the opportunity for an even more elite level of cut quality – the super ideal.

Super ideal vs Ideal cut diamond vs Excellent cut

Round and Princess Ideal Diamonds
When optical precision is taken into account (also known as optical symmetry or 3D symmetry), there are really three levels of Excellent. The first is the broad GIA designation, with the AGS Ideal grade sitting inside as a higher level. A diamond that has the AGS Ideal grade and also possesses a top level of optical precision, such as is demonstrated by a true pattern of hearts and arrows, constitutes the ultimate level in what is accurately referred to as a “super ideal”. Claims of super ideal therefore need to be documented with evidence of 3D symmetry in the form of advanced light performance imaging such as hearts and arrows scope or ASET light maps. It should be noted that a significant number of merchants use the term without providing that evidence, so those claims should be viewed with skepticism.
Ideal Cut Diamond
Super Ideal Cut Diamond
Ideal vs Super Ideal Cut Diamond
Modern understanding of the extreme importance of diamond cut quality has created demand for ultra precise diamond craftsmanship culminating in the availability of “super ideal diamonds”. A round super ideal such as the A CUT ABOVE® not only has the highest cut grade from the AGSL (Triple Zero), but also exhibits near-perfect hearts and arrows patterning. These diamonds are capable of drawing light from even the dimmest lighting environments and returning maximum light to the eye in sparkles of flash and fire scintillation. They represent the ultimate combination of extreme precision, proven light performance and extraordinary beauty in a diamond.


When it comes to diamond cut quality many shoppers are more than happy with a diamond that bears the GIA designation of Excellent. But those who are prioritizing cut quality and light performance are demanding more than a broad grade that includes diamonds that are not superior performers along with those that are. The collaboration between GIA and AGS, and the new AGS Ideal addendum report from GIA, now provides a way for shoppers to identify the truly exceptional performers in the Excellent grade. For shoppers looking for the best-of-the best there are super ideals that are all that and more; Excellent, Ideal, and possessing top levels of optical symmetry.

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