Post by Richard Sherwood » November 12th, 2003, 12:52 pm
ormal style="MARGIN: 0in 0in 0pt">I’m often asked if diamond grading is an exact science. In other words, if one grader calls a diamond a VS-1, is every grader going to call it a VS-1?




My answer would be that diamond grading is a scientific, subjective analysis using distinct parameters to judge by. A close analogy to the process would be the judging and grading of an athletic event such as a diving competition in the Olympic Games.




In an Olympic diving competition, there are eight or nine judges who will grade the dive. These judges are well trained in what makes a “perfect” dive, and they take off points accordingly for any “imperfections” in form or execution. Their analysis however, is subjective, so when they all “hold their cards up” there might be a slight difference in grade from judge to judge. For the most part though, they will be in close agreement.




It is the same with diamond grading. If you take eight or nine qualified gemologists and have them grade the same diamond, their grades should ordinarily closely agree, with possibly a couple grading slightly higher or lower. If you have a diamond that is a “borderline” grade, half the graders may call it a (low) VS-1 and the other half may call it a (high) VS-2. This is to be expected, and in reality usually affects the value level relatively slightly.




You can throw this analogy out the window though, if the following is introduced into the equation:




- Jewelry or gemstone professionals who have not been specifically trained in diamond grading handing out grades.


- Individuals grading without the supporting equipment (microscope, master stones, etc.)


- Individuals grading with an inherent bias (they’re selling the stone, or have a vested interest in its sale.


- Laboratories lacking strict quality control on their grading process.




How do you make sure the grading on your gemstone is credible? First, paying a little extra to buy a stone or have a stone certified by the “icons” of the industry is a great investment. Some names are world renowned, with few people questioning their grades. GIA, AGS, HRD, and the North American EGL labs come to mind.




The names mentioned above are the “majors” of the big league lab world. Following them is a host of “minors” who vary in their excellence. I tend to rank them as the minor league baseball teams are ranked- Triple A, Double A & Single A labs. The Triple A labs are often the equivalent of the Major League Labs in their integrity and excellence, without the instantaneous name recognition (although many are well known in their own right within the industry).




These labs are a good “double check” on the majors, as well being recognized for having their own quality grading controls. In addition, many offer additional services not given by the majors, such as photos, ancillary tests, more in-depth descriptions, insurance values, and face-to-face answers to all your questions.




Whatever you do, have your diamond checked out by professional. Being that it’s the most concentrated form of wealth known to mankind, you want to purchase it with more research than you put into ordering your next pizza.

Rich, non-Independent GG Appraiser
Sarasota Gemological Laboratory