Diamond Laboratory Reports are NOT the Same!

Posted by on Saturday, May 17, 2014 · Leave a Comment 

These days, most diamonds of 1.00 carats and over, and many diamonds under 1.00 carats, are sold with independent laboratory reports which authenticate the natural origin of the diamond, provide its weight, measurements and quality information. Most jewelers purchase their diamonds with laboratory reports, and most jewelers rely on the report to represent the diamond. Historically, even though the 1950’s, jewelers relied on their own knowledge of how to judge a diamond’s quality and value, and communicated that knowledge to each client, creating the trust so necessary for the purchase. In the 21st century, the public appears to rely on the content of the report itself, and may assume, correctly or incorrectly, that their jeweler has enough independent knowledge to be able to explain the report, and to make certain the report does in fact represent the diamond. This transfer of the public’s trust in a jeweler to their trust in a report, made by unknown persons in a laboratory thousands of miles away, is at the heart of the problems presented by these reports, and how they are used and misused to create representations about the quality and value of a diamond.

Here are some simple rules to follow when purchasing a diamond with a laboratory report:

1. Is the jeweler using the report to represent the diamond, or is the jeweler himself or herself representing the quality of the diamond, and merely using the report as corroboration, and for insurance purposes? If the jeweler is relying solely on the report, and cannot independently determine the quality of the diamond, then you may wish to rethink this method of buying your diamond. You want your jeweler to be able to verify that the report is in fact the correct report on the diamond, and you may also want your jeweler to be able to analyze the diamond himself, so that he can discuss those features which are not part of the laboratory report. They may be significant, and material to making you an informed consumer, ready to make your purchase.

2. Some laboratory reports use the same or similar grading scales for the two rarity features of a diamond, the color and the clarity. However, using the same scales DOES NOT MEAN that the laboratories interpret the grades identically. In fact, this has become a huge problem in the report business. Some laboratories interpret the grades of color very liberally, and will grade a diamond’s color 2 to 5 grades higher than classic grading technique developed and represented by the GIA Gem Trade Laboratory, and which has become the internationally accepted grading methodology. Jewelers use such laboratory reports to create the illusion that the client is getting a much better diamond for much less money. If the client is comparing diamonds in several stores with the same color and clarity ratings, the diamonds which have been graded with GIA or AGS reports will appear to be more expensive. In fact, they are more expensive because they are much finer diamonds, with much better color and or clarity, than the diamond receiving the same grade with the liberal grading report. Example: An “H” color provided by a particular laboratory will be a “K” color when graded by the GIA. Countless consumers have fallen for this illusion, and do not find out until much later, when they have their diamond identified and appraised by a GIA graduate gemologist and appraiser. Many never find out, until some day years down the road, they wish to upgrade or perhaps even sell their diamond, and find out then that it was never the grade they thought it was, and never the value either.

3. Ask your jeweler to explain the grading scales on the report for your diamond, and how those scales may differ from those used by the GIA or AGS. What would your diamond be graded if it were sent to the GIA, and how might that affect its current and potentially future value? Why did your jeweler choose a diamond with this kind of report? If possible, have your jeweler compare the color of your diamond to a set of master comparison stones pre-graded by the American Gem Society or the GIA, and determine what is “true color” is on those scales.

As long as the public prefers to value diamonds based on letter and number grades on reports, and is relying on the report rather than on the experience and integrity of the seller, then it is imperative that the public understands the meaning of the grades on the lab report, and how that grade and then the value may differ when the diamond is submitted to a different laboratory.

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