ความรู้เกี่ยวกับเพชร การตรวจเช็คและระบุตำหนิภายใน ภายนอกของเพชร

DIAMOND PLOT

Because a photograph cannot capture the subtleties of clarity, GIA uses a diamond plot to map a diamond's interior and exterior flaws. A diamond plot is a graphic representation of every flaw that affects the overall clarity grade. The flaws are found under 10x magnification by a skilled grader.

 
Example GIA Diamond Plot: The Key To Symbols section
shows the flaws in order of severity

While the plot shows the type and position of each flaw, the actual visibility of the flaw is communicated in the diamond Clarity Grade itself (i.e. two diamonds may have very similar plots, but very different Clarity grades, reflecting the actual severity and visibility of the recorded flaws).

Besides the plot, there is also a comment section on the certificate where additional clarity characteristics are often noted. These are usually too minor to be reflected in the plot itself. Between the plot and the comment section, all inclusions visible under 10x magnification are accounted for.

http://www.lumeradiamonds.com/glossary/GIA_Grading_Report