Reading Diamond Certs : Plot

It is impossible to achieve absolute consistency in diamond grading because nature does not give absolute demarcations when it creates diamonds. Therefore, grades may vary somewhat from lab to lab when a diamond is somewhere between two grades. But the main thing most consumers want to know about a diamond is very simple: “Does the diamond have any flaws I can see with my naked eye?”

Usually you will be able to answer this question using the Plot, or map of the Inclusions and Blemishes in a diamond.

If a diamond has a clarity grade of VS1 or better, you will not see anything with the naked eye, as long as the diamond has a GIA or AGS certificate.

However, it becomes a little harder to make that statement about a VS2 in ALL cases, because placement and description of the inclusion(s) can make a difference.

If the clarity grade is VS2 or less, we recommend examining the plot to see the placement of the major inclusions.

Below are the main two examples of using the plot to help avoid issues when the grade is SI2, SI1, or even VS2. Higher grades will not have issues, if your cert is from GIA or AGS.

  1. If the inclusions are shown in the top view (the table view), it means the inclusions are located closer to the top of the diamond. If they are in the center of the table, and in the top of the diamond, they might be easier to see, even the clarity grade is SI2 or SI1. This could be especially likely if the inclusion that defines that grade is a single or few larger ones, instead of many smaller ones.
  2. If the inclusions are in the bottom view (the pavilion view), the inclusions are closer to the bottom of the diamond. Some inclusions in the pavilion can reflect and multiply, creating the illusion of a ring of white, similar to looking at infinite images of yourself when you are standing between two mirrors.

Neither of these are common, but they are worth asking about if you find them in your plot.

See our Glossary of Terms to find out more about any of the terms used on your certificate, such as Feather, Pinpoints, Cloud, Needle, or Natural.

Here is an excellent image from the AGS website to show how a plot is drawn on a certificate ::

Screen Shot 2013-12-06 at 5.53.05 PM


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