Inclusions and irregularities are normally present in diamond, as are exterior defects. To determine the purity of a diamond, the expert examines the stone under a microscope from below, aimed at a source of light. Certain inclusions are not detectable for the average observer and in this case, the laboratory estimation alone can determine the threshold S12, which certifies that the defects are not perceptible to the naked eye. A high degree of purity does not necessarily mean that the diamond is beautiful. Indeed, great clarity does not improve the appearance of the diamond, but rather will determine its rarity and its price. The SI2 threshold is recommended.
|FLAWLESS (FL)||Absence of internal and external defects with a magnification of 10 times.|
|INTERNALLY FLAWLESS (IF)||No inclusions with 10 times magnification; in practice, with a dimension of less than approximately 5 μm. Pure. We can also find these appellations: Pure under the magnifying glass 10 X ou Clean Magnifier (LC).|
|Tiny inclusion (s) very difficult to see with a 10 X magnifying glass.|
VVS = Very Very Small Inclusion (s).
|Very small inclusion (s) hardly visible with a 10 X magnifying glass.|
VS = Very Small Inclusion (s).
|Small inclusion (s) easily visible with a 10 X magnifying glass, invisible to the naked eye from the side of the crown. It should be noted that the SI3 classification is not recognized by expert laboratories (GIA, HRD, EGL; etc…) but it is used by diamond dealers and appears on the Rapaport. SI = Small Inclusion (s).|
|P1||Inclusion (s) very easily visible with a magnifying glass 10 X, hardly visible with the naked eye when viewed from the side of the crown and not affecting the shine. P1 = Stitched 1.|
|P2||Large and / or numerous inclusion (s) easily visible to the naked eye from the side of the crown and slightly affecting the shine. P2 = Stitched 2.|
|P3||Large and / or numerous inclusion (s) very easily visible to the naked eye from the side of the crown and distinctly affecting the shine. P3 = Stitched 3.|
The method used evaluates the size, location and visibility of inclusions (see diagram as an example for a round diamond)