Labs may differ on your diamond’s quality

Grading reports from well reputed gemological laboratories should provide an unbiased assessment of diamonds and give detailed insights that might not be obvious to the consumer or retailer. A high quality report would include the basic characteristics of the diamond, reveal any treatments or inclusions and help value the diamond for purposes of insurance or resale. Few labs also provide an inscription service to identify ownership or origin of the diamond.

Even though the purpose of all grading labs is the same, grading report formats differ in terms of findings covered and technique of presentation. It thus becomes important for consumers and retailers to familiarise themselves with such varying reports from leading labs.

RapNet had conducted a study by sending similar diamonds to leading grading labs – GIA, IGI, HRD, EGL USA, EGL Israel and EGL Hong Kong. They compared grading reports to spot differences in grading across the 4Cs and rated each of the labs in order of strictness. The general finding was that labs across US are most strict and non-US labs are more lenient.

Idex Online did a more detailed study for close to 12 million diamonds from their online index and came to similar conclusion that grading varies across labs – some labs consistently grade higher than others. A key reason why grading is inconsistent across labs is that it’s still largely a manual process. Each person’s opinion can differ for clarity and color of a diamond. The study provides a detailed analysis on the grading tendencies of each of the labs.


 GIA sample report


[Image Courtesy: GIA]


Various studies also vary on the leading labs of the world – RapNet study did not include AGS whereas the Idex Online one included it as part of top 6 labs across the world that handles 78% of all grading requests. Besides, there are differences of opinion on the terminologies used in the report. Such variations make it even harder for the users of the report to evaluate the diamond.

From point of view of retailers, differences in grading reports creates an issue for convincing consumers about the real quality of the diamond and its appropriate pricing. Should the diamonds graded by strict labs be priced higher? What if a diamond is priced high due to its high quality rating from a lab and other lab grades it lower thus reducing the resale price? Is it worth grading every diamond considering that the grading process also adds to the final price? These questions call for better regulations across labs, and better third party information disclosure to consumers.

Nevertheless, one thing is absolutely certain – Such inconsistencies and variations in practices of gem-labs have a direct fallout on consumers and other industry stakeholders equally, and Gem-labs should stop having multiple schools of thought.



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