How Different Labs Grade Clarity

The world jewelry confederation set rules for grading laboratories such as the gemological institue of america or gia, american gem society or ags that have specific requirements for their grading system and criteria for grading clarity in diamonds.

The two most respected gemological laboratories in the world today are GIA, Gemological Institute of America, and AGS, American Gem Society. The grading guidelines that each of these two laboratories have set up meet and exceed CIBJOs, Confederation International de la Bijouterie, Joaillerie, Orfevrerie des Diamantes, Perles et Pierres, or more simply, The World Jewelry Confederation, rules, and have set the bar for all other laboratories. Each has their own nomenclature for their respective grading systems.

GIA uses the following labeling in their grading system:

• 13FL: Flawless
• 14IF: Internally Flawless
• 15VVS1 and VVS2: Very, Very Small Inclusions (two separate grades)
• 16VS1 and VS2: Very Small Inclusions (two separate grades)
• 17SI1 and SI2: Small Inclusions
• 18I1 and I2: Inclusions Visible

AGS uses a numerical system that runs from 0 to 10 in its grading system. Side by side, the two systems line up as so:

• 0 = FL
• 1 = IF and VVS 1
• 2 = VVS 2
• 3 = VS 1
• 4 = VS 2
• 5 = SI 1
• 6 = SI 2
• 7 = I1
• 8 = I1 and I2
• 9 = I2 and I3
• 10 = I3

You can see that the two systems have slightly different range of the particular grades. What is important to remember with this is that the nomenclature for a particular grade may be different, but the grading criteria and requirements for each are quite rigorous and strict, more so than the laboratory grading systems found elsewhere.