Which Diamond Lab Certification Is Best?

When purchasing a diamond we want it to come with a certification specifying the parameters of the stone, hence the quality of it.
Which Diamond Certification Is Best?

The question we should ask ourselves is – does the diamond certification that comes with the diamond describe the stone accurately?

Sadly enough, the answer to this question is a definite No.

In this post we will discuss the different laboratories in the diamonds world and reveal all the secrets and warning concerning natural diamonds that are graded by different gemological institutes.

I am sure that many traders in this industry will not like this post which will expose and show the difference between the diamond certification.

Let’s start with the biggest problem the consumer is facing when purchasing a certified diamond.

  • Original diamonds are a natural resource that comes from the ground. It’s not a patent which makes it harder in defending the consumer.As a natural resource, anyone can open a diamond laboratory and grade the diamonds based on his eyes only.

    The problem is that there’s a price list for diamonds based on their weight, color & clarity.

    Therefore, for example, if a strict lab will grade a diamond as F VS1 for which the price list in 1 carat is around $10k, another lab which we nickname as “fun lab” and much less strict will grade the same diamond as D IF or VVS and by that the “value” of the diamond will go up in the price list to $16k-$18k per carat.

This “loose” grading works to the benefit of the seller, but not the consumer.

When a client comes to purchase a D IF diamond and pays $12k for a “fun lab” certificate (without knowing the reliability of this lab), the owner of the shop tells him he got a bargain since he’s paying much less than the market price while in fact he has paid around 20% more as the diamond is a real F VS1 and its’ price list is much less than D IF.

This is a classic example for the saying “what’s cheap is expensive”.

Now let me tell you the differences between the 5 most popular labs.


GIA certified diamonds is known worldwide as the top and most reliable diamond certification for diamonds as it grades the diamonds for what they really are.

Therefore, all other labs grading are compared to GIA’s.

When comparing HRD lab to GIA usually there’s a difference of 1 grade in color to ½ in clarity.

Meaning, some of the top color & clarity get a better grading in HRD, so in this case I will say there’s a difference of 1.5-2 upgrades in HRD comparing to GIA.

Both in the cut and fluorescence the two labs are quite similar.


In color and clarity IGI is quite similar to HRD.

Maybe in the top TOP colors with syndicate pure rough there are 2 upgrades of color & clarity in IGI.

Not only this, but a GIA medium or strong fluorescence will get slight or very slight in IGI.

Another difference is the cut grade – IGI is a bit easier than GIA, so basically you can have the same diamond E VVS1 with strong blue fluorescence in GIA certificate or D IF with slight fluorescence in IGI certificate (sounds much better in writing).


Here the difference in the grading can be between 2-4 in color (EGL USA lab is a bit stricter than other EGL labs, and the difference can be only one grade in color).

Clarity is usually between 1-2 upgrades in EGL.

Meaning, if you purchase a diamond with EGL certificate you can find yourself buying a diamond with 6 upgrades on the certificate (which doesn’t reflect the stone itself at all).

If you do decide on purchasing a diamond with EGL certificate then go for either EGL USA or EGL Platinum as among the EGL labs they’re considered to be the strictest.


AGS is known especially because of the triple zero certificates that put a great emphasize on the cut of the diamond and the light reflection.

Also, in this lab you can see 1-2 colors upgrade and a ½ in clarity.

I have mentioned the main laboratories, but there are so many others all over the world that only very few of them give an accurate grading that reflects the stone itself.

As mentioned above, GIA is the no. 1 lab in accuracy. After GIA, there are IGI, HRD and AGS.

Most of the other labs are very loose in their grading and are in favor of the seller.

So, when buying a certified diamond, make sure what lab it is and go for certificates that are traded between wholesalers as it will be much easier selling it in the future.

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Dianoche PTE Ltd. is a diamond manufacturer registered in Singapore, as well as a diamond jewellery retailer. Our company is comprised of veterans in the world of diamonds and high-end jewellery.

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