A certificate is tells you the diamond's exact measurements, weight, quality
and the details of its cut. It precisely points out all the individual
characteristics of the stone and also serve as proof of the diamond's identity and value.
The following is a list of well known diamond certification authorities,
GIA clarity grading is performed under 10x magnification with darkfield
illumination using standard equipment binocular stereo microscopes.
These microscopes are also equipped with an ultraviolet light
filtered overhead light.
This is one of the leading certification authority in diamonds.
The American Gem Society grades clarity on a number scale between 0 and 10 and correlates almost exactly with the GIA system but with some differences. The flawless and internally flawless (0) grades are grouped together with notation defining whether the stone is free from external blemishes, the VVS through SI grades are numbered 1 through 6, and then there are four grades 7 through 10 for the included category.
Clarity grading by AGS standards requires examination using a binocular stereo
microscope equipped with adjustable zoom magnification and darkfield illumination.
This is one of the leading certification authority in diamonds.
The IDC or the International Diamond Council uses a very similar standard to CIBJO. IDC loupe clean stones that have external blemishes have notations made on the grading report. IDC clarity grading is by examination using a 10x achromatic, aplanatic loupe in normal light.
The European Gemological Laboratory (EGL) introduced the SI3 as a clarity grade. While intended as a range to include borderline SI2 / I1 stones, it is now commonly used to mean I1's which are "eye clean", that is, which have inclusions which are not obviously visible to the naked eye.
The CIBJO or the International Confederation of Jewellery, Silverware, Diamonds and Stones developed the International Clarity Scale for grading diamonds. This clarity scale mirrors the GIA grading scale, except nomenclature varies. The CIBJO system names these clarity grades; Loupe Clean, Very, very small inclusions (VVS1 and VVS2), Very small inclusions (VS1 and VS2), Small inclusions (SI1 and SI2), Pique (P1, P2, and P3).
Clarity grading by CIBJO standards is by examination using a 10x achromatic, aplanatic loupe in normal light.