GIA Certification, Explained

When buying a diamond, its price is not the only thing that you should consider. It is after all, a smart investment. And this means that there are plenty of other factors to look at, with quality being one of them. It’s true what they say – quality and price do go hand-in-hand.

That is why it’s so important to have your diamond carefully evaluated. After all, you want to be taking home only the best! And the GIA, the IGI and the HRD are three bodies that will help you out with that.

The GIA report

What is a GIA diamond?

To put it quite simply, a ‘GIA diamond’ is essentially a term that diamond sellers use to refer to diamonds which have been graded by the GIA. What is the GIA, you ask?

The GIA is the Gemological Institute of America and is quite an important body when it comes to grading diamonds. GIA is an independent entity that carries out gem research, trains gem professionals and truly raises the bar when it comes to defining diamond quality. Above all, its one key function is diamond grading.

How does GIA evaluate a diamond?

The GIA evaluates or grades its diamonds carefully. This careful evaluation happens just for you and is based on a variety of factors. This includes, apart from the 4 Cs, the diamond’s evaluation date, its girdle thickness and its polish grade, to name a few. In fact, the 4 Cs system of rating diamonds was actually first established by the GIA, back in 1953.

The GIA also maintains stringent measures when it comes to rating diamonds on the basis of Colour and Clarity. It even holds an excellent reputation for these ratings.

What to watch out for in a GIA report

A GIA report is usually very detailed. Here are a few things that you should check for

yourself once you have the report in hand:

  • Check the issue date!
  • Check if it talks about the shape and cut of the stone
  • It should include data on the dimensions and carat weight of your diamond
  • Your diamond’s proportional symmetry must be mentioned
  • Keep an eye out for the mention of the unique report number
  • Look for mentions of the colour grading and clarity grading of your stone
  • You can also ask for a fully coloured and detailed picture of your diamond to be included in this report!

GIA Certification Styles

It is a truth universally acknowledged that the GIA sets the benchmark for diamond certification. There are certain certification styles that come under the GIA that you ought to know about. Two of the key ones include the Diamond Grading Report and the Diamond Dossier.

The Diamond Grading Report

This report comes with an entire 4Cs analysis. It also offers a clear plotted diagram on the clarity of your diamond. This report stands just for loose, D-to-Z colour diamonds that weight 0.15 carats or more than that.

The diamond grading report

The Diamond Dossier

True to its name, this dossier is pretty comprehensive. It comes with a complete 4Cs assessment and a GIA report number laser inscription, which holds a great deal of value for buyers. This stands for loose, D-to-Z colour diamonds that weight between 0.15 to 1.99 carats.

The diamond dossier

Other certification reports and styles include the Diamond Focus Report, the Diamond Report and the Diamond Origin Report, of which the last two are online reports.

How to read a GIA Proportion Diagram

Reading a GIA Diamond Grading Report is not as difficult as you may think it is. Once you have the basics in place, it’s pretty easy to understand it for yourself. In fact, it is said that if you can read a GIA report, you can just as easily read reports from other diamond grading entities.

Take the clarity plot diagrams, for starters. It is a pictorial representation of any marks that your diamond may have. So when you’re taking a look at these diagrams, here’s what you should watch out for.

The clarity plot diagram

Remember that external blemishes are always marked in green while internal inclusions are always marked in red. The report will also feature a proportions diagram of your gem stone. If you’re looking at analyzing your diamond based on factors such as its girdle thickness or its depth percentage, this diagram is for you. Its proportions will be listed right beside the diagram in percentage signs or in degrees, so look closely.

The proportions diagram

In such diagram, the indication of a culet and the diamond’s girdle thickness are also showcased. But if your diamond is of a more modern and brilliant cut, a culet is generally omitted, as the presence of a large culet will tend to cause the appearance of your stone to take away from its general appeal.


More often that not, the GIA is considered to be the gold standard of diamond grading. Apart from grading precious stones and providing certification for them, the GIA is involved in educational services, too. But of course, there are other labs that grade diamonds as well.

The IGI, for instance. Known as the International Gemological Institute, it is the second best grading lab in the world, after the GIA. A large chunk of diamonds in the market today are graded by the IGI. It is also said that when it comes to pricing, the IGI is about 12% cheaper than the GIA. According to several case studies, the IGI is also stricter than the GIA when it comes to colour grading.


It cannot be reiterated enough that the GIA is viewed as the most reputable grading lab in the world, following the strictest standards. But the Hoge Raad voor Diamant (HRD) or Diamond High Council is almost as popular as the GIA.

The HRD is considered to be 95% as strict as the GIA in the grading of stones. Largely, the GIA is actually the strictest in terms of colour grades. The HRD is the one lab that most closely adheres to the GIA’s stringent standards.

The GIA  also offers a separate grading for both polish and symmetry which the HRD combines under one sole heading titled “finish.” The HRD also includes a clarity grade called as “Loupe Clean”. This category isn’t offered by the GIA.

Uniglo Diamonds offer GIA, IGI and HRD Certified Diamonds.

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