AGS ASET Technology

Angular Spectrum Evaluation Technology® (ASET) was developed to demonstrate – in red, green, and blue – how the diamond is performing – in other words, how the diamond is handling and returning light to our eyes. Red indicates the brightest areas of the diamond – areas that attract the brightest light from above. Green also indicates light return; however, from an indirect source which is not as bright. The blue indicates a contrast pattern of dark reflections giving the diamond its personality.

Unnamed %281%29This is an ASET® image of an AGS Ideal® performing diamond. There is a lot of red, some green, and a distinct pattern of blue. The blue pattern resembles arrows, an indication of the symmetry of the diamond.


Unnamed %282%29This is another ASET® image of an AGS Ideal® performing diamond. Although the blue “arrows” are not as distinct as in the image above, the pattern is symmetrical, not clustered or dominant over the entire diamond.


Unnamed %283%29This is an ASET® image of a poorly cut diamond. Although there is some red in the center, the lack of any pattern in the blue and dominance of green demonstrates that the diamond is NOT performing to its potential. You can also see black, which indicates light that is lost entirely.


Using the colors of red, green, and blue, the ASET® provides a unique “thumbprint” of your diamond, documenting its light performance and beauty. After viewing a collection of diamonds, you can decide which unique “personality” is most appealing to you. Then, your AGS jeweler can explain how performance, proportions & finish affect the overall cut grade of a diamond, helping you make the best value decision – for a most important buying decision!

Presentation ASET



The Presentation ASET has high-grade optics through which you and your customer can easily view the optical performance of loose or mounted diamonds. The ASET can be used to demonstrate the light handling capabilities of a faceted diamond. With the ASET manufacturers will make better decisions when cutting diamonds, retailers will make better decisions with diamond selection, and consumers will make better buying decisions. Available to AGS members only

When a diamond is viewed through the ASET, a color-coded image is seen. The different colors show the angles from which the diamond gathers light:
Green = 0º (horizon) to 45º
Red = 45º to 75º
Blue = 75º to 90º


Red represents light coming from angles where there is likely to be bright, direct sources of illumination in most viewing environments. This color is dominant in the ASET image of a well-cut diamond.

Blue corresponds to light that normally is blocked by the viewer’s head and body. An ASET image with a moderate amount of this color in an attractive pattern means the diamond has good contrast.

Green is produced by low-angle light, which usually is reflected from walls or other objects in the surrounding area (rather than coming from direct sources). A diamond with a high cut quality may show small amounts of this color around the bezel area of the ASET image.

Black or White appears in areas that do not return light under real-life viewing conditions. If a diamond is well cut, the ASET image will show only very small areas of black or white around the outer edge (and perhaps none).

Green = 0º (horizon) to 45º

Red = 45º to 75º

Blue = 75º to 90º

Black or White = indicates leakage