How does the HRD certificate compare to GIA certificate?
GIA is the oldest lab and so has become the most well-recognised and reputed, especially in the U.S. On the other hand, HRD whilst well-regarded by the diamond community in Europe, is a rather unknown report in the U.S. Whilst HRD and GIA differ ever so slightly in systems of grading both strive to conform to their own system and overall, they both do good and comparable jobs. You should to be able to buy a diamond with a high degree of confidence with either lab's report.
Here are some of the differences that have been observed by a fellow diamond professional in Antwerp when working with both GIA and HRD certificates for the same diamond:
"Colour-grading: Experience with both labs teaches me, that in the very high colours (D-E-F), HRD is generally more strict than GIA. In Antwerp, I try to buy specific HRD higher range E-colours, and very often, I get a GIA D-grade for them. The other differences between the two labs are minimal.
Clarity-grading: GIA is generally slightly stricter in clarity-grading than HRD. For borderline-impurities, GIA will give one clarity lower than HRD.
Proportion-grading for round brilliant diamonds. GIA did not use to give a grade on proportions but introduced a new cut grading system from January 2006, whereas HRD has been operating a cut grading system for many years where prior to 2009, the highest grade for cut proportions for round brilliant diamonds was 'Very Good'. Since January 2009, HRD Antwerp has refined its cut grade, and now grades the diamond’s proportions, polish and symmetry which are the same factors as GIA grades. The polish describes the finish of the facets, while the proportions determine the brilliancy and the fire of the diamond. The symmetry describes the variations of the different parameters that define the proportions. For diamond professionals, the range of grades (Excellent and Very Good are the top two grades in both GIA and HRD certificates) from both these labs is too broad to be really useful however, some information on this is better than no information at all.
Symmetry- and Polish-grading. GIA gives separate gradings for Symmetry and Polish, with the highest possible being 'Excellent', while before January 2009, HRD used to combine Symmetry and Polish into a Finish-grade where the highest possible grade was 'Very Good'. Since January 2009, HRD Antwerp has refined its cut grade, and now grades the diamond’s proportions, polish and symmetry separately which are the same factors as GIA grades separately.
Detailed information. GIA gives you table size, total depth, while HRD gives you table size, crown height and pavillion depth, while you can calculate total depth yourself from the measurements. When giving girdle size, HRD uses another notation than GIA, and because of that the girdle will appear about 1.7% thicker on a HRD-report than on a GIA-report.
These are the main differences. Now to politics. Working in Antwerp, and having thousands of HRD-reports available here, I do not understand why HRD does not do a better job of promoting its report in the U.S. I fear that politics is the reason behind this. A few years ago, GIA was apparently preparing to set up a lab in Antwerp. Somehow, this lab has never started, and HRD is now heavily promoting its report in Canada, Dubai, the Far East, but not in the U.S. Could there be some kind of gentleman's agreement between the two labs? "
