I was looking through some AGS ideal cut diamonds online and noticed something peculiar about the AGSL Computer Generated Light Performance Map. In some grading reports, some of the diagrams showed a green circle in the middle of the diamond and on some others, I noticed they were red.
Green or red center in a round brilliant cut diamond? Which is better?
Based on the articles I read on your website on the ASET images, my takeaway is that we should see as much red as possible. My question is, since the amounts of red would affect light return, shouldn’t the diamond with the green center be graded with a lower cut grade?
In all of these examples, AGS has graded all of them as triple 0s. Shouldn’t they look identical? If so, why do they apparently have different light performances?
Answer: The circular center that you are referring to is actually caused by the reflection of the table facet on the pavilion facets. The size of the table reflection is determined largely by the table size % and the pavilion depth %.
Diamonds with 60.2%, 54.4% and 69.0% table sizes
Technically speaking, the table reflection does not indicate light return or performance since it is a phenomenon caused by reflections in the diamond. Typically, a green reflection is caused by pavilion angles of less than 40.7°.
The center could appear red, green or even as a mixture of both and that’s still fine. In the case of both triple 0s ideal cut diamonds that you had chosen, the color of the table reflections in ASET images won’t impact the physical brilliance or outlook of the stones.