Fancy color diamonds (FCDs) are rare and because of this they are also more expensive than colorless diamonds. The rarest and most expensive fancy color diamonds are pink and green and a large pink or green diamond with a vivid color can been sold at auction for millions of dollars per carat. Even if you’re not in the market for an FCD, I think you will learn something about diamond color for colorless diamonds.
When grading a fancy color diamond, GIA will issue a Colored Diamond Grading Report. The fancy color grades are the following:
- Very Light
- Fancy Light
- Fancy Intense
- Fancy Dark
- Fancy Deep
- Fancy Vivid
Remember that diamond color is always graded from face-up no matter if it’s a colorless or fancy colored diamond.
Let’s review the color grades from colorless to fancy vivid.
DEF is the colorless range, GHIJ is the near-colorless range, KLM is the faint range, N to R is the very light range, and S to Z is the light range. Most diamonds on the D-Z scale have a yellow undertone and are only truly considered ‘fancy’ at the fancy light yellow (FLY) range. Brown diamonds that are K-color or lower will also have a colored grade issued (i.e. L and faint brown). Grey diamonds that are K-color or lower will only have a colored grade issued.
Try to avoid any diamond that has a brown or grey of undertone because these are usually traded at a 10% or more discount compared to diamonds with a yellow undertone. It’s amazing to me that even with a smooth scale that there can be such a huge price difference between a low-end Cape series diamond and a fancy light yellow diamond.
How to Pick a Fancy Color Diamond
The most important thing a prosumer needs to know is that FCDs do not receive a cut grade like a colorless diamond. The reason is because fancy colored diamonds are graded and valued primarily by the intensity of their color from the face-up view. The good thing about fancy color diamonds is that although cutting them is more complicated than a colorless round, for the consumer it is actually pretty simple. The only considerations for a consumer is whether they like the color, and then ensuring the color is even and as stated on the certificate. Finally an understanding of how rare the particular stone is will help you understand its value. For example, natural green, green-blue, and pink diamonds are some of the rarest fancy colored diamonds and command the highest premium.
The colorless round brilliant cutting philosophies where perfect symmetry and polish are positives do not apply for fancy colored diamonds. The concepts of brilliance where optimising for brightness and contrast also do not necessarily apply. In fact, contrast in a FCD can be seen as a negative because it may be detrimental to the overall evenness of the body color. Reducing contrast is the first method of color retention in fancy color diamonds.
Just because a FCD might not have perfect symmetry and polish, this does not imply that FCDs are cut imprecisely; in fact quite the opposite is true. Cutting a FCD is much more of an art than cutting a colorless diamond. The reason is because sometimes the diamond may exhibit a certain overall intensity but is more intense in some parts of the diamond and less intense in other parts. The reason is because the impurities (nitrogen in the case of yellow diamonds) have not been introduced evenly as the diamond crystal was growing. This is known as color zoning, which also explains the faint to light range of diamonds in the Cape series.
A good cutter will plan the cutting of a fancy color diamond to maximize color entrapment. This begins by identifying the cutting axis and positioning the culet in a way that maximizes color. The cutter can also manipulate the crown/pavilion relationship, the upper/lower girdle indexing, the twist, adding extra-facets, or even leaving in parts of the rough to retain a better overall color. Fancy color diamonds are difficult to plan and cut because the cutter needs to balance maximizing the carat weight and the color. As always, the price will determine how the diamond will be cut.
Transforming Cape to Fancy Color Diamonds
Sometimes, low colored Cape series diamonds can make good candidates to be transformed into FLY diamonds given the right cut. It is highly debatable whether transforming these lower value diamonds into highly sought after fancy diamonds is ethical, especially as it can be seen to be masking the fact that these diamonds are not ‘true’ fancy color diamonds. Should a diamond which has been made into a FLY from a low colored Cape be as valuable as a ‘true’ FLY? This is a question best answered by the market. That, however, assumes that consumers can make an informed decision after given all the facts. My personal opinion is that FCDs, and perhaps all diamonds, should have two color grades, a face-up and a body color grade. In such a system, a colorless diamond that faces-up D-color but has G body color will be more valuable than one that has G face-up and body color. In the same way, a FCD that is graded with a FLY face-up color but an X body color will be less valuable than one that is both FLY in both face-up and body color.
Whether transforming a diamond into a FLY or improving the appearance of a FCD by making the diamond color even throughout the diamond, the cutter has to employ the color retention techniques mentioned above. One of these methods to retain color in a diamond is to cut the diamond in a way that the light entering the diamond bounces around more times before leaving the diamond. As a general concept, the more times light bounces (undergoes total internal reflection), the more color is retained in the diamond. This is known as color entrapment.
This is the reason why certain shapes are more favourable for color and why most fancy color diamonds are cut to fancy shapes rather than a round brilliant, which happens to have the best performance in terms of brilliance but is actually the worst shape for color retention. The way fancy shaped diamonds accomplish more internal reflections is because of the extra crown facets and extra pavilion facets that some have over the round brilliant.
Color Entrapment in Cape Series Diamonds
In order to think how color retention can affect Cape series diamonds, we can draw on some of the concepts we already know about brilliance and turn them upside down. For example, we know that relatively shallower pavilions increase contrast and it turns out that steeper pavilions help color retention. This would also suggest that crown-only painting of the girdles and shorter star lengths, which decrease contrast in a diamond, will have the same effect. The point to remember is that if you want your diamond to appear whiter, then that is more of a reason to optimise for brilliance.
In Cape series diamonds, color entrapment is a negative because if you are looking at J color diamonds, you probably want it to face-up whiter to ensure it stays in the near-colorless range rather than falling into the faint color range. You should be aware that a steeper pavilion angle will lead to increased color that is visible from the face-up view meaning that J will look more yellow.
It has been suggested that you will begin to see the effects of color entrapment with pavilion angles over 41 degrees. Color entrapment begins to be an issue for diamonds with tight tolerances at a pavilion angle of 41.4 degrees, with the effects becoming more obvious when the pavilion angle is 41.6 degrees and over. The reason is because the light entering the diamond through the girdle is likely to reflect internally many times off of opposing crowns and pavilion facets. Logically, the problems are worsened when more light enters the diamond through a thicker girdle. Face up, it has been suggested that the color will be most likely seen around leakage areas (ie. in the upper girdles and under the table). Also, for fancy shaped Cape series diamonds, the effect of color entrapment is also more evident than in rounds as the previous discussion would suggest. For example, in a princess cut, the corners of the diamond is more likely to experience color entrapment issues.
Please note that a lot of this depends on the color distribution in the particular diamond in the first place. Remember that diamonds that look differently can receive the same color grade because color is graded on color depth, which is a combination of tone and saturation. At the end of the day, all this does for us prosumers is that it raises additional concerns when picking diamonds in the hopes that they will appear whiter than their stated grade. You can only verify the existence or non-existence of the effect of color entrapment upon a visual inspection, and even then only if you have comparison stones available and have a pair of color sensitive eyes.