Should reports include hue?

Through it all, the Gemological Institute of America (GIA) developed a grading scale and terminology with the main goal of creating a standardized system for evaluating colour in a unbiased and accurate way. The colour grading scale starting at D to Z removes the biases of the previous scales by using terms that didn’t in any way imply or suggest the whiteness or lightness of a diamond’s hue.

Unfortunately, there is growing opinion that this colour scale is incomplete. As important as clarity and colour are to a stone’s cost, in some cases, hue can also be a factor when determining final price. While it’s my belief that indicating hue on a diamond report would be welcomed by many buyers, cutters and sellers would likely be in disagreement to do so.

Although an informal opinion, it comes with experience gathered in the early stages of our laboratory being established in India. I have found there was, and continues to be, a significant amount of resistance against additional information being included in reports (i.e. hue) that can further divide the diamond grading scale. In other words, diamond cutters and traders don’t want laboratories providing additional information that can possibly be used to shrink profit margins.

Without accounting for a diamond’s hue, a generalized colour scale allows each stone to be marketed as the sellers see fit. It would be up to the seller to emphasize the diamond’s yellow hue, and therefore, charge a premium. In the case of diamonds in the brown range, it is up to the seller to draw attention to the positive aspect of the diamond other than its hue.

As for gemmological laboratories, I am sure many would side with the seller, though not for the same reason. Instead, a gemmologist would suggest that to keep an unbiased opinion, only the diamond’s colour intensity needs to be observed and recorded. The addition of the stone’s hue is not a gemmological requirement, since the colour scale is only a measure of intensity. If labs were to include hue on reports, they would have to develop a new set of parameters to identify this property in brown and yellow diamonds.

Though I am making an assumption, when I put on my scientific gemmological hat, I find this may be the only reasonable argument against adding hue to the colour grade. However, the obvious counter would be that universally, all gemmological reports are used to buy and sell stones. Further, it can be said a report’s details with a certain set of values has a corresponding price, which is based on the price lists that are readily available. It would also be reasonable to say that if reports have a certain value, and there was information that could possibly further impact a stone’s price, should it not be added so that a buyer is fully aware of a diamond’s characteristics to make an informed purchase decision?

Although I started putting this article together with a set of ideas of how I felt about this subject, while writing it, I can see how difficult it would be to pick one side and follow it through. The unfortunate thing is this issue cannot be resolved until a comprehensive, universally adopted scientific standard language is accepted amongst gemmological laboratories. Until then, we will do our best with what we have.

Hemdeep Patel is head of marketing and product development of Toronto-based HKD Diamond Laboratories Canada, an advanced gemstone and diamond laboratory with locations in Bangkok, Thailand, and Mumbai, India. He also leads Creative CADworks, a 3D CAD jewellery design and production firm. Holding a B.Sc. in physics and astronomy, Patel is a third-generation member of the jewellery industry, a graduate gemmologist, and GIA alumnus. Patel can be contacted via e-mail at contactus@hkdlab.ca or sales@creativecadworks.ca.