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Diamond Certificates

A diamond certificate is extremely important when buying a diamond or any diamond jewellery. It validates the quality of the diamond, ensuring its authenticity. At Steven Stone we supply GIA certified diamonds only

Diamond Certificates

A diamond certificate serves the purpose of the stone's passport. This authenticating document is issued and printed by an independent laboratory. The certificate informs buyers whether or not the diamond is natural and lists its key attributes and qualities.

There are five primary diamond laboratories. Only two of the labs listed below have an excellent reputation when it comes to grading of diamonds. GIA and AGS are world-renowned and the most respected diamond laboratories. GIA actually invented the current diamond grading system we use today, and are therefore the benchmarking authority in diamond grading. AGS are usually known for grading higher quality diamonds with ideal cuts and proportions, which are generally more expensive.

The Main Diamond Laboratories

Gemmological Institute of America
The Gemmological Institute of America

GIA is the world’s foremost authority on diamonds. GIA is the leading source of knowledge and standards for gems and jewellery

American Gemological Society

The American Gemological Society

The AGS is famous for its scientific approach to diamond grading, ethical standards and consistency

Diamond High Council

The Diamond High Council

The HRD is a private foundation established in 1973 as the Diamond High Council and represents the Belgian diamond industry

International Gemmological Institute

International Gemological Institute

IGI is the largest diamond and coloured gemstone grading laboratory

EGI-Logo--2154.png

European Gemmological Institute

EGL has first introduced diamond clarity rating and specializes in grading diamonds weighing less than a carat 

There are many more diamond certification companies around the world, however they do not carry a great deal of authority and as such, should be treated with caution.

Gia and AGS diamond certificates

A certificate does not necessarily mean you should buy with absolute confidence. We would strongly recommend that you only shop diamonds with GIA or AGS certificates when purchasing diamonds online, as these are the only two which actually provide strict and accurate diamond grading.

 

GIA Certificate

 

Less distinguished diamond certificates often assess a diamond as being anything from one to three colours or clarity grades higher, compared to a GIA or AGS certificate. This is why other websites may, on the face of it, seem to offer comparable diamonds at a better price (up to 10% cheaper), but in reality won’t be comparing equivalents.

For instance, if a G colour diamond graded from the GIA was graded at EGL, it could be graded as an E colour. So if you were to compare the price of an EGL E colour and a GIA E colour the price could be as much as 20% more, but it will not look the same. It would be cheaper to buy the GIA G colour than the EGL E colour and both would appear the same, so if you were to actually compare identical diamonds, the GIA certified diamond would be better priced.

Just because the diamond grades may be lower, it does not by any means suggest that the diamond would lack life - it only means you won’t actually be getting what you think you are paying for.

To illustrate how much price affects quality -  A 1ct round diamond can vary between £2,500 and £20,000. Both diamonds would weigh the same, however the diamond colour and diamond clarity would be different. That's why we recommend trusting only GIA and AGS, especially when buying via the internet.


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