The charts above are clarity plots, which is a representation of the number and size of inclusions typically present in diamonds of a particular clarity grade. Look for a clarity plot on a diamond certificate, or grading report, to get a clear idea of the number and size of inclusions in a particular diamond. From this map, you can perfectly determine a diamond's clarity without even seeing the diamond.
Clarity determination factors
Gemologists use grades of clarity to describe how many inclusions a diamond has. These grades range from flawless (FL) or internally flawless (IF) to included (I3), with the numbers indicating varying degrees of quality within a grade (1 being the best). Most commonly diamond sold are diamond that has no inclusions visible to the unaided eye, like VS1 and SI1-2. Diamonds of this clarity are much less expensive than flawless diamonds, and will not contain inclusions that would reduce from the splendor of the diamond