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Why Diagram Diamonds?

Diagraming a diamond’s inclusions and blemishes, commonly called plotting, is taught to every gemologist trained by the Gemological Institute of America (GIA). And, we encounter them in diamond laboratory grading reports, commonly called certs. But what use are they in appraising? Well, from the perspective of the gemologist-appraiser a plot substantiates the clarity. But that can be accomplished merely by adding a hand drawn plot in one’s working notes – and not including a plot in the appraisal report. Some appraisal and gemological societies have requirements in their standards that a plot be rendered in an appraisal if a diamond exceeds a certain weight.1 But what about the appraisal customer?

Think of your Customer

Assuming that your customer is going to use the appraisal to insure their diamond piece, would it benefit them to submit an appraisal with a plot? The answer is yes.

Firstly, the plot documents the diamond at the time of inspection. Thus, if a chip occurs later on – the customer can verify damage has occurred and submit a claim. That would not be easy to do if the diamond were perhaps an I3 in clarity since a chip might be what made the diamond such a low clarity grade. By the way, in some cases, a customer cannot get insurance if a diamond is chipped2 – or the insurer will require a plot or micro-photograph, in addition to a statement by the appraiser about the stability of the chip.3 Also, plotting a diamond avoids intentional false claims and that avoids insurance fraud.

Secondly, some insurance companies, such as U.S.A.A. require plots for diamonds of a certain clarity, size and value.4

Think of Yourself

Lastly, the professional image of the appraiser is bolstered if a plot is part of the appraisal. Look at what your competition does – they most likely avoid plotting or charge extra for such a service. And, if their customer uses U.S.A.A., they will see an unhappy customer return.

But …

The time to add a plot into an appraisal is why most gemologist-appraisers avoid plotting. What if I could teach you to render a professional looking plot in full color in less than three minutes, that’s right – I said three minutes? Just watch the webcast below. It will present to you Hoefer’s Technique for plotting diamonds.

Best to view at full screen - lower right-hand box in controls has option - to revert back, press the ESC key.

I am not a fan of war stories but I once did an appraisal for a woman which included a plot. She went to a store that did a lot of remounts. They sold her on the idea of remounting her diamond because she could watch them do it. She was right next to the goldsmith while he was modifying the semi-mounting. A salesman on the opposite side of the store dropped a full cup of coffee on a tile floor. Everyone suddenly found themselves staring at the broken cup and coffee splatters on the floor – with the salesperson waving his hands in the air crying out it was his favorite cup. While the woman was staring at this mishap – the goldsmith switched the diamond with another of less quality. To make a long story short … the diamond plot in the appraisal for the old ring was the evidence that they had stolen her diamond used in court.

Bill Hoefer



1. The American Society of Appraisers (ASA) places this requirement at 0.50 carats and above.    Back to Text ↑ ↑ ↑
2. State Farm has this standard.    Back to Text ↑ ↑ ↑
3. This is the Jewelers’ Mutual standard.    Back to Text ↑ ↑ ↑
4. Their standards are in a webcast in the subscribers’ area of this website.    Back to Text ↑ ↑ ↑





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