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Differences in Diamond Grading

Differences in Diamond Grading

Each of our diamonds is certified by one of the following professional independent organisations:

GIA Gemological Institute of America
EGL USA European Gemological Laboratory USA
AGS American Gem Society Laboratories
HRD Hoge Raad voor Diamant (Diamond High Council)
IGI International Gemological Institute

Here’s where things get a little bit confusing. Whilst all these laboratories do a lovely job of certifying diamonds, they don’t always agree on how diamonds should be graded. They each have their own specific criteria for determining the colour and clarity grades and some laboratories are stricter than others. As the following table shows, a diamond graded as G colour, VS2 clarity by GIA would be graded E colour, VS1 clarity by EGL USA.

Colour Comparisons GIA AGS HRD IGI EGL USA
Whitest D D      
Ultra White E E D    
Very White F F E D D
White G G F E E
White H H G F F
Very Slight Yellow I I H G G
Slight Yellow J J I H H
Clarity Comparisons GIA AGS HRD IGI EGL USA
100% 10 x Loupe Clean FL/IF IF      
100% 10 x Loupe Clean to the untrained eye VVS1 VVS1 LC/LC+ IF IF
100% 10 x Extremely Clean with Loupe VVS2 VVS2 VVS1 VVS1 VVS1
100% Very Clean with 10 x Loupe VS1 VS1 VVS2 VVS2 VVS2
100% Eye Clean VS2 VS2 VS1 VS1 VS1
90% Eye Clean SI1 SI1 VS2 VS2 VS2
50% Eye Clean SI2 SI2 SI1 SI1 SI1
Not Eye Clean I1 I1 SI2 SI2 SI2
Not Eye Clean I2 I2 I1 I1 I1

You might be wondering how you can possibly compare diamonds when the certifying laboratories can’t even agree! But don’t worry – this is one reason why we developed our unique DiamondScore.

DiamondScore takes these grading differences into account and gives you one clear mark out of ten for each diamond, so choosing the best quality diamond couldn't be easier.

Find out more about DiamondScore here