The American Gem Society recently released an incredible device to assist us in showing our clients why a well cut diamond is so beautiful.

It is called the ASET, Angular Spectral Evaluation Tool. This device shows us where the light coming to our eyes out of a diamond is actually coming from. It tells us instantly and visually which diamonds are going to look the best, and more importantly, it tells us why.

It looks like a very simple tool, yet it provides an astonishing amount of information.

Many people do not realize that the vast majority of the light that we see coming out of the top of a diamond, actually enters that diamond from the top of the diamond, that is why it does not matter to a well cut diamond whether it is in open prongs or a full bezel. This wonderful tool shows us exactly where the light is coming from and we will attempt to explain to you why that is important.

Here is what we are seeing when we look into the ASET tool.

As you can see, light from 0° to 45° shows as green in the resulting image. This is usually a softer light than is gathered into the diamond from above 45% as it is normally ambient light and reflected light off of walls etc.

The red light is from 45° to 75° is usually brighter overhead light whether from the lights in your room or the sun overhead, it is much more intense than the ambient lighting and it is highly desirable that the diamond have more red light than green.

The blue light is caused by obstruction from the head of the viewer and provides very valuable contrast which increases the on/off flashes that make the diamond exciting. Without the contrast we might as well have a small mirror in our rings. They would return 100% of the light striking them, but unless you get really excited by looking in a mirror they would be rather boring.

The following slides will illustrate this for you. The first will show why we need contrast and also discuss the fact that humans are hard wired to detect edges.

The second will show some poor contrast patterns, to help you see why it is important to have a quality cutting pattern that will give you excellent contrast and increase that on/off sparkle that makes our diamonds speak so loudly to us when they are well cut.

Also this slide will show why that is important, as a well cut diamond will have a frequency of sparkle that is better than you get with a poorly cut diamond.

Here is a brief discussion of leakage in a diamond and how it affects the beauty of your diamond.

And here the discussion continues about brightness and the effect of leakage especially when we look at stones like the fish eye (too shallow) and nail heads (too deep). You will notice that the fish eye gathers a LOT of red light, but it looks lifeless because there is not a good pattern of contrast to break up the brilliance, which actually makes the stone look less bright to the human eye.

We will finish this report with a few examples of diamonds from our inventory that we have taken photos of. The first is a 1.11ct I-SI2 EightStar. Since the photos are magnified you can easily see some of the inclusions if you look carefully. Notice the incredible pattern and the total lack of leakage in this diamond.

The next diamond is a 1.65ct. G-VVS2 from our Cut by Infinity line of Hearts and Arrows cut diamonds. No visible inclusions here, but there is a minor amount of leakage as shown in the diagrams above.

If you would like to know more about this information you can download the entire presentation from the American Gem Society that was presented at the Las Vegas Jewelry Show in June of 2005. Just click here for the full presentation.

Also available is a PDF file on the Foundation, Research Results and Application of the New AGS Cut Grading System.

We would like to express our appreciation to the American Gem Society, specifically to Jim Caudill for helping us to be able to take photographs through the desktop ASET and for Pete Yantzer for the excellent work he and his team did on this presentation and for giving us permission to share with you.