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Certificate Comparisons

The Essential 7C's

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, 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:


  Sold by 77DIAMONDS Not sold by 77DIAMONDS
  GIA HRD IGI EGL INT. In-house Certificates
White D D D+ D+ D+
White E E D D+ D+
White F F E E+ D+
White G G F E D
White H H G F+ D/E
Extremely faint yellow tint I I H F E/F
Very faint yellow/brown tint J J I G F/G
Faint yellow/brown tint K K J H G/H
Yellowish/brownish tint L L K I H/I
Medium to strong yellowish/brownish tint M M L J I/J
Strong yellowish/brownish tint N N M K K/L
Very strong yellowish/brownish tint O-P O-P N L L/M

*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

Ancora una volta, con chiarezza, si dice che il GIA sia il più rigoroso, assegnando almeno una categoria inferiore rispetto a tutti gli altri laboratori. L'HRD aggiunge la sua propria categoria di purezza alla scala tradizionale, definendo tutte le pietre con impurità invisibili con una lente 10x come "Senza imperfezioni al microscopio". A causa di questa categoria aggiuntiva, le pietre classificate come IF o FL dall'HRD riceverebbero solo un grado VVS1 dal GIA. Lo stesso vale per IGI, EGL, che assegnerebbero tutti un grado di chiarezza tra uno e due gradi superiore rispetto al GIA, il che significa che un VVS2 su un certificato GIA. Si prega di fare riferimento alla tabella qui sotto per confronti più dettagliati*.


  Sold by 77DIAMONDS Not sold by 77DIAMONDS
Clarity Description GIA HRD IGI EGL INT. In-house Certificates
100% Eye Clean FL/IF LC+ IF+ IF+ IF+
100% Eye Clean VVS1 LC-/VVS1 IF-/VVS1 IF+ IF+
100% Eye Clean VVS2 VVS2 VVS2 IF+ IF+
100% Eye Clean VS1 VS1 VS1 IF IF+
100% Eye Clean VS2 VS2 VS2 VVS1/VVS2 IF+
80% Chance SI1 SI1 SI1 VVS2/VS1 VVS1/VVS2
10% Chance SI2 SI2 SI2 VS1/VS2 VVS2/VS1
Not Eye Clean I1 P1 SI3 VS2/SI1 VS1/VS2
Not Eye Clean I2 P2 I1 SI1/SI2 VS2/SI1
Not Eye Clean I3 I3 I2 SI2/SI3 SI1/SI2
Not Eye Clean N/A N/A I3 I1 SI2/SI3

*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.

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