Certificate Comparisons

The most renowned and trusted gemmological grading laboratories are the Gemological Institute of America (GIA), the Hoge Raad voor Diamant (HRD), the International Gemological Institute (IGI), and the 2 versions of European Gemological Laboratory (EGL International). From these 5 laboratories, the 3 that set the standard are the GIA & HRD.(Search for GIA & HRD diamonds)

The GIA is widely regarded as the most reputable and recognized grading laboratory in the world, with the strictest standards. Founded by the creator of the GIA. The Hoge Raad voor Diamant (HRD) or Diamond High Council is almost as renowned worldwide as GIA but not as popular and it is 95% as strict in its grading. (Search for GIA diamonds)

BEWARE: Even though these are the 5 leading international diamond certification organisations their grading criteria do vary and are not equally strict. Please be aware of the differences when choosing your diamond (see below).

All the certificates differ slightly in layout, terminology and grading systems, with some including diagrams and symmetry or proportion grading and others being simpler. However, the two main grading aspects to consider when comparing certificates are colour and clarity, for their evaluations largely determine the price of a diamond and yet they are not consistently graded across the board. A colour grade, for instance, may differ in up to two grades (sometimes more) from one certificate to another and yet this is not always reflected in the price, so beyond understanding simply how colour or clarity grades work, it is essential to know how to interpret and compare them.

Beside the 5 types of certificates that we offer on 77Diamonds.com, there are a multitude of other types of certificates not always independent, such as “in house” certificates which are typically graded more generously even than EGL International certificates and which cannot be compared with independent internationally recognised certificates. 77Diamonds does not sell any in-house certificated diamonds.

Certificate Comparisons for Colour

Overall, the GIA tends to be the strictest on colour grades, and out of the other laboratories, HRD is the most closely adhere to the standards set out by the GIA. IGI tend to give one colour grade higher than GIA, and EGL up to 2 colour grades higher. So an F colour stone on a GIA certificate would most likely be the same on HRD, an E on IGI, and a D on EGL. Please refer to the table below for a more detailed comparison* (note: table is based on Seventy Seven Diamonds’ experience:

CERTIFICATE COMPARISON ON COLOUR GRADING

*Note: Although not published anywhere, these differences are generally accepted within the diamond trade as correct and are also based on 77 Diamond’s experience.

Certificate Comparisons For Clarity

Again, with clarity the GIA is said to be the strictest, giving at least one grade lower than all other laboratories. The HRD adds its own clarity grade to the traditional scale, terming all stones with impurities invisible with a 10x loupe as 'Loupe Clean.' Because of this extra category, stones grades as IF or FL by the HRD would only receive a VVS1 from the GIA. The same applies for IGI, EGL which would all grade between one and two clarity grades higher than the GIA, meaning that a VVS2 on a GIA certificate. Please refer to the table below for more detailed comparisons*.

CERTIFICATE COMPARISON ON CLARITY GRADING

*Note: Although not published anywhere, these differences are generally accepted within the diamond trade as correct and are also based on 77 Diamond’s experience.

Click here to read more about diamond clarity.

Other Differences Between Certificates

The main other differences between the certificates lie in the differences between GIA, HRD. GIA gives separate grading for symmetry and polish which the HRD groups together under the heading of \"finish.\" HRD also includes one clarity grade termed “Loupe Clean” which is not offered by the GIA.

Click here to read more about diamond cut.

Learn More

• Certificate Comparisons
• Individual Grading Laboratories & Certificates