HomeBlogDiamond certifications
Last Updated June 2024 - 6 articles


These blog articles educate and train to compare the different diamond certification options. How do diamonds compare when certified by GIA vs AGS, GIA vs EGL, GIA vs IGI, and GIA vs HRD.

The Diamond Certification Checklist: What to Look for Before You Buy

by Willyou.net * Jun 20, 2022

Key Takeaways

  • No shopper should ever consider investing in a diamond that is not accompanied by a legitimate diamond report from an established and reputable grading lab.
  • A diamond report or ‘certification’ records every aspect of the diamond’s quality. Together, these aspects are what decide a diamond’s value – and whether or not it’s the right investment for you.
  • Some diamond labs are far more reliable and consistent than others. The GIA and AGS are the only labs we would recommend to shoppers, while less reputable labs like the GSI tend to be far more advantageous to vendors, rather than their customers.
  • Uncertified diamonds are untrustworthy, and so are the sellers who encourage shoppers to buy them.
GIA certifications

It’s pretty common for a first-time shopper to enter into the process of buying a diamond unaware of the fact that how it has been graded – and who it has been graded by – is central to their ability to avoid wasting their money, or picking out a dud.

So, consider that your first lesson – never let yourself be one over by an ungraded diamond, no matter how good the deal looks, and never waste your time on anyone attempting to sell you one.

A diamond’s grading is verified by independent laboratories that assess diamonds. While some research labs are rigorous and consistent, others are not as concerned with detail and inconsistent in their grading. When purchasing a diamond, you need to be sure that you are paying the correct price for its true quality.  

 To make sure you purchase a diamond that is high quality, Willyou.net recommends using its advanced diamond viewing tool, which displays diamonds with GIA or AGS certification – the most reputable lab out there. Our team has witnessed many gross mistakes from a lot of the major gemology labs, and we want you to make an informed decision. 

Never forget that when buying a diamond, you are buying a precious stone – one that you cannot possibly understand completely without consulting its accompanying report. If you’re a little uncertain about the paperwork or anything else, do not hesitate to ask for help from our experts.

What is Diamond Certification?

Diamond certification (usually from the GIA, AGS, IGI, EGL, GSI, and HRD laboratories) is a document you receive from a third-party objective laboratory describing a diamond in all of its characteristics.

Along with any diamond you are considering, you must receive and revise the lab certification. This laboratory report or certificate is issued by an assessment body and describes various elements of the diamond, such as color, clarity, length, and width. Trained professionals evaluate, examine, and measure the diamonds with professional tools, such as a magnifying glass or microscope.  

Each entity rates and describes diamonds differently – and sometimes, the difference is significant. There are several lab entities, and it is essential to know which ones are reliable and trustworthy and which are not. 

Because diamond certificates are not created equally, the price and value of diamonds are not comparable between different certifications. Make sure you buy a diamond with a certificate from a highly reputable grading agency – and that you take a close look at the diamond before buying it. 

If you have a diamond in mind and would like an expert assessment of the certification, please contact us.

Is it Ok to Buy a Diamond Without a Certificate?

No, this could prove disastrous and, in all likelihood, lead to you paying a much higher price for a low quality diamond.

First of all, a diamond without a certificate either has not been certified – if this is the case, then it’s value cannot be accurately determined – or has been certified, but the seller wants to fetch a much higher price than its true value. Either way, anyone attempting to sell you an uncertified diamond cannot be seen as reliable.

Of course, it could be the case that the diamond is not even a real diamond at all. It might be any number of diamond simulants that, to the untrained eye, appear to be real until you compare them with a genuine diamond. Common diamond simulants are not worth anywhere near as much as real diamond, meaning that, once again, you’re at risk of overpaying by potentially thousands of dollars.

What to Look for in a Diamond Report

Laboratories that prioritize consistency over rigor and excessive detail in their evaluations are far more valuable to you. Some things don’t require as much attention as others, so don’t fall into the trap of thinking that the most exhaustive report is the best one for you.

There is no ‘one way’ to grade a diamond, and each laboratory takes its own approach. Some prefer to give a concise overview according to a number of very precise scales, while others will offer insights into many, many different aspects and, in so doing, spread themselves thin.

For example, the GIA will not rate a diamond in the same way that the IGI rates a diamond. The reliability of the color and clarity grades – and in some cases the cut grades – is only as good as the certification lab’s reputation. But, if one lab consistently gives a single clarity grade higher than another lab, that lab’s results are going to be far less valuable to you.  

Why? Because, in many cases, the difference between two different grades amounts to hundreds – even thousands – of dollars, meaning that you could end up paying more for a diamond that has been graded higher than it should have been.

To emphasize the importance of this problem, take color gradations as an example. We recommend sticking with an H color or better when placing a diamond in a setting like this. You may think you have found a bargain with an IGI certified H-color diamond. But once you get it home, you realize that the diamond has a yellow hue because it is an I color through GIA certification. The IGI offers a weak and invalid certificate.      

Remember that judging diamonds is always going to be subjective process – and contrary to popular belief – there is no central organization that mathematically defines what a “G” color is or what “SI1” clarity looks like. However, that some labs have devised much, much more consistent methodologies than others.

Is Consistency All that Matters?

No – since all grades are used to determine a diamond’s market value.

It is important to note that even when an entity is consistent in its assessment, it does not necessarily mean that it is trustworthy and reliable. Buying a diamond with an invalid certificate for a high price is not wise, even if the entity consistently rates diamonds in this way because you are not getting the value for the price you pay. 

Different certification laboratories give different results.

Each lab has its quirks. Some are looser in the assessment of color, while others are looser in the evaluation of clarity. Some labs will always upgrade specific color ranges, while others prefer particular arrangements of inclusions.  

Innovative diamond companies use this knowledge – gained by sending thousands of diamonds to different labs every month – to maximize their results. Knowing which labs are reliable and consistent can help you avoid buying a diamond worth much less than its certificate. 

Consider the price above the certification. Regardless of the certificate you receive, the diamond’s price must be judged heavily. The price should reflect the actual quality, beauty, and cut of the diamond – both on the certificate and to the naked eye. 

If you are unsure whether a diamond is authentic or overpriced, have a diamond expert review it before purchasing it. For questions about diamond prices and certifications, please contact us.

Which Diamond Certification is Best?

The best diamond certifications are the GIA and AGS, as they are the most consistent laboratory grading entities. That means you can rely on their rating in all aspects, such as color, clarity, and cut quality.

These labs also assess more rigorously than other labs. When a diamond comes with a GIA or AGS certificate, you can trust what the report says. That is why we recommend that you only buy diamonds with GIA and AGS certificates.   

Here’s a little more about these two leading diamond labs…

GIA certification

The GIA (Gemological Institute of America) is the most respected and renowned diamond grading entity. They are incredibly consistent and provide the utmost peace of mind when buying a diamond.

The GIA has no financial interest in the sale of the diamond and grades diamonds on a variety of qualities and elements, including:

  • Diamond’s Evaluation Date

This is important, because a very old GIA report may not account for certain signs of wear and tear, such as chips or scratches.

  • Dimensions (in millimeters)
  • Cutting style and diamond shape
  • Carat weight

The GIA first weighs diamonds to three decimal places the presented within the report to two decimal places.

Both are vital to ensuring that your diamond features the right proportions and, as a result, that it is able to sparkle as much as the cut promises.

A highly important factor to consider, although not as talked-about as the Four Cs.

  • Laser inscription (if applicable)
  • Security features
  • General remarks

The GIA has a reputation for more rigorous reviewing the color and brightness rating, the most subjective scales. Due to GIA’s excellent reputation, proven consistency, and history, we recommend that you only buy diamonds with a GIA or AGS certificate.

Even the largest jewelry insurance company writes:

“The most reliable diamond certificates (also called diamond reports) come from the Gemological Institute of America (GIA) and the American Gem Society (AGS). These are the most respected labs, known for their accuracy and professionalism. These reports are not and do not contain appraisals. Certificates from other sources are often questionable, and insurers should not rely on them.”

For more information, you can read our full guide to GIA Diamond Certification here.

solitaire round diamond engagment ring

AGS Certification

The AGS (American Gem Society) is proud to be the original laboratory to provide diamond cut grades. Long before the GIA introduced their cut grade a few years ago, the AGS offered its unique cut grade scale from 0 to 9 (with 0 being called “ideal”). 

At the time, the AGS had a monopoly on the “ideal cut” market. A diamond cannot be referred to as “ideal” unless it has an AGS certificate that says so. Now that the GIA has entered the cut-grade game, however, their share of this market has fallen significantly.  

The AGS generally tries to call itself a bit more upscale and refined than the GIA. In reality, there is hardly anything to distinguish the two labs from each other. AGS is still the preferred choice for many retailers selling perfectly cut round diamonds.

To find out more about the AGS, take a look at our full guide here.

The Downside to AGS Certification

The only problem to watch out for is “upgrading shopping”. No laboratory is 100% accurate, as color and clarity are not objective qualities (such as weight and dimensions). If there is a diamond somewhere in-between grades, a manufacturer or retailer can send the diamond to multiple labs looking for a better quality assessment. Suppose a diamond has a weak I color or a strong J color, and they have received a J color from GIA. The wholesaler/retailer can try to send it to AGS for the I color (they can then sell it for more money). It’s much more likely that the numbers will be the same, but they may get the upgrade (which more than makes up for the cost of shipping to AGS for certification).        

It is common for companies to use AGS for super ideal brand diamonds. But AGS is not that commonly used for non-round diamonds. So if a retailer has 50 cut cushion diamonds, 49 of which are GIA certified and one AGS diamond, that diamond has likely been upgraded.  

This is not a knock on AGS but an observation of how some wholesalers and retailers can take advantage of the end consumer. All in all, AGS is a very reliable laboratory. We only recommend diamonds certified by GIA or AGS, and we only partner with suppliers who highlight these two labs.  

Other Diamond Grading Labs

While we don’t recommend any of our readers invest into a diamond that has been graded by one of the other labs, it is important to understand why they are considered inferior so that you don’t feel tempted by an apparently ‘good deal’ further down the line.

To further learn how IGI classifies, we sent four diamonds to different lab entities, including the IGI, EGL, GSI, and HRD, for clarity and color classification. Since these two categories are the most subjective, we knew they would tell us a lot about how IGI rates diamonds. 

Below, we will look at the other labs – and the grades they assigned to each of our four diamonds.

IGI certification

The IGI (International Gemological Institute) started as the workhorse of the diamond business. IGI is like a factory: they work fast, and their prices are much better than GIA – which appeals to diamond sellers but not necessarily the end consumer.

While IGI considers itself a top-notch laboratory, this is, unfortunately, not the case. From extensive experience in the diamond industry, we have consistently seen that their grading is lax and less consistent than industry standard-bearers such as GIA. 

In 2005, Dateline raised serious questions about IGI’s integrity concerning their rating values.

According to our own research her are the diamond color and clarity grades that were given by the IGI:

Diamond 1Diamond 2Diamond 3Diamond 4

IGI results

We look into the IGI’s grading methods in more detail in our guide to IGI diamond certification.

EGL Certification

The EGL (European Gemological Laboratory) – firm and inconsistent – is inflating their quality claims. If you’re considering an EGL certified diamond, you may think you’re getting a better deal. In reality, the price is very high for an inferior product.  

Unfortunately, we have seen many customers buy an EGL certified diamond thinking they have found a good deal but realize they have fallen into a sales ploy. We wish they had hit the contact button earlier so we could help them make an informed purchase. 

As an example of one of these sales tricks, we found an EGL Certified 1.00 Carat H VS1 Ideal Cut online for $ 4,450. At first, it seems like an incredible deal. However, if EGL claims to be an H VS1, it is, in fact, a J SI1 50% of the time – and 50% of the time, it is a J SI2 or K SI1: no H VS1.  

Suppose you are looking for a GIA Certified diamond with two or three color grades lower or one to two clarity degrees lower. In that case, you will ensure that you are buying a higher quality diamond at a lower price.

The bottom line: don’t buy an EGL-certified diamond. No matter how “cheap” it seems to you compared to GIA-certified diamonds, it’s all a game. Every EGL certified stone on the market is by definition more expensive than it would be if its value had been determined based on a report by the GIA.

As proof, we sent the same four diamonds to EGL to receive gradations of color and brightness – the most subjective scales.

 As anticipated, the EGL rated the diamonds higher than the other labs. For example, an EGL diamond with a clarity of VS2 is not comparable to a VS2 from the GIA. For this reason, the price and value of an EGL diamond are incomparable and dissimilar to a diamond certified by GIA.    

In addition, the two EGL labs that assessed these diamonds offered different results. The inconsistency between the labs makes it challenging to trust the assessment and verify the true quality and value of an EGL diamond. 

Diamond 1Diamond 2Diamond 3Diamond 4

EGL results

Diamond 1Diamond 2Diamond 3Diamond 4

EGL Israel results

If you need any more information about the EGL’s approach to grading diamonds, you can find more in our full guide to EGL diamond certification.

HRD Certification

HRD (Diamond High Council) is a diamond appraisal organization based in Europe. Not widely regarded as a legitimate alternative in the United States, HRD still claims to be the authority for diamond grading in the world. 

 Over the years, we have experienced incredible inconsistency in assessing HRD. They usually average about two classes, whether color or brightness, above the GIA rating. HRD diamonds are typically priced much higher than equivalent diamonds rated by the GIA. This allows diamond companies to make significant profits.   

To compare HRD assessment and other labs, we sent four diamonds to different lab entities. The chart below shows that HRD rated the same four diamonds better than the GIA in the Color and Clarity categories: two highly subjective grades. 

The clear difference between the sorting shows that it is not wise to compare apples to apples between lab entities. Simply put, an F Color grading given by HRD does not mean the same as a GIA F Color diamond. The price you pay for an HRD diamond cannot be compared to the value and quality of a GIA diamond, even if it is a grade or two higher.  

Diamond 1Diamond 2Diamond 3Diamond 4

HRD results

If you are considering an HRD certified diamond, we recommend that you reconsider your choice immediately. For more information, however, you can read about the HRD’s methods

GSI Certification

The GSI (Gemological Science International) is a new classification entity that has only been around for a few years. Unfortunately, they did not come to the industry with fresh ideas or innovative technology. They built their business by calling on the major retail chains in the United States. 

 Scoring those big companies means millions of dollars in business. The Capital Forum alleges that GSI took business away from IGI by opening a lab just down the street from their headquarters to make it easier to collaborate and significantly undermine their prices. 

We found that the GSI rating is looser than the gold standards (GIA and AGSL labs) and weaker than the next level down (IGI and HRD). GSI also does not maintain consistent grades, such as trying to lower the numbers 1 or 2 grades and calculating the value. 

For these reasons, we do not recommend buying a diamond that has a GSI certificate. We strongly recommend that you only buy diamonds that have a GIA or AGS certificate. By doing this, you know what you are getting and can compare apples to apples. Retailers don’t use inaccurate certificates like GSI to offer consumers a better deal; they do it to make more money from those consumers.    

 To show how GSI rates diamonds compared to other labs, we sent four stones to GSI, IGI, HRD, EGL, and GIA. For the color and brightness grades – the two most subjective categories – we got markedly different results. 

GSI rated some of the diamonds higher than the GIA and some lower, making it difficult to determine the consistency of a GSI rating. When shopping for a diamond, it is critical to choose a diamond certified by a trustworthy, consistent entity, such as the GIA, so that you know that what you are buying matches the true value of the stone.

Diamond 1Diamond 2Diamond 3Diamond 4

GSI results

Check out our full guide to GSI Diamond Certification for any more information you might need before you make up your mind. 

Frequently Asked Questions

It’s all very well and good us recommending one lab to you but, when it comes to a purchase this big and this important, it’s not always easy to know quite where to put your faith. The best thing you can do is educate yourself and, in doing so, realize the importance of relying only on those labs that are non-profit, and widely accepted across the global diamond industry.

How Vital is a Diamond Certification?

Diamond certification is essential for any diamond as it verifies and describes what you are buying.

Without a certificate from a trustworthy lab, there is no way of knowing if the diamond you are buying is what the seller is claiming. A diamond certificate contains details such as the cut quality, color quality, carat weight, and other characteristics. Having proof of what you are buying is paramount, especially with such a large purchase as a diamond.   

Does My Diamond Need a Certificate?

Yes, your diamond needs a certificate because there is no way of knowing what you are buying without it.

A certificate provides proof of carat weight, cut quality, color quality, clarity, and more. Without a certificate, you are not even sure whether the diamond is real or synthetic – let alone whether it’s worth your time and money, or not.

Diamond value is calculated based on a wide range of factors, most of which can be found in the report. Each one drives the value up or down, which means that any diamond’s value is grounded within logic.

A diamond that has not been formally graded by a reputable lab cannot have its value accurately judged. Without those grades, you can only guess at its quality – and that could easily mean that you are paying thousands of dollars more than you should be.

What is the Difference Between a Certified and Non-Certified Diamond?

A certified diamond has been assessed by a third-party lab and comes with a certificate, while a non-certified diamond has not, and offers no guarantees about its quality.

Certified diamonds are more trustworthy because a professional gemologist has verified them. With a non-certified diamond, it is difficult to know if aspects such as the color and cut quality of the diamond are what the seller is claiming to be. That is why we only recommend certified diamonds from the renowned laboratories of the GIA and AGS.   

Anyone can get a loose diamond certified, and the easiest route is by bringing it into a trusted jeweler who understands the process of submitting a diamond for grading at one of the GIA’s labs.

It is important to note, however, that the easiest way to ensure the quality of your diamond is to ensure that it already has a full GIA report. This is the most effective way for you to avoid the risk of investing into an inferior diamond, and to ensure that your money is being put towards the highest level of quality possible – whatever your price point.

And, as we mentioned above, the GIA will only grade loose diamonds, meaning that any settings will need to be removed by a skilled jeweler prior to grading.

Can a GIA Certificate be Fake?

It’s possible to fake a certificate, but not the Unique Report Number included within it.

As a result, it’s impossible to create a forgery that can dupe anyone who understands how to verify authenticity. For some underhanded vendors, this is a pretty enticing prospect, as it means that they are able to win an inexperienced buyer’s trust with a few forged grades that suggest a low quality diamond has been very highly graded in clarity or color – and is, as a result, worth thousands of dollars.

When you consider the number of diamonds that are bought and sold on any given day, instances of forged GIA reports are relatively uncommon – and not something you need to worry about if you are working with reputable vendors.

Yes, it may lure a few unsuspecting people in every once in a while, but there is a fool proof way of ensuring that you are not being duped into paying thousands for a diamond that has not been graded by the GIA’s experts.

The Bottom Line

Buying a diamond represents a pretty major learning curve for most people. It’s not uncommon for buyers to second guess their own ability to judge a ‘good deal’, and to know when they might be making a mistake. This is particularly true when they start to learn more about quite how many features influence a diamond’s quality and beauty – and, of course, how many of those features require an expert eye to spot.

The only way to avoid that self-doubt and anxiety is to be able to put your faith in independent resources capable of shedding light on the positives, negatives, and overall value of your diamond.

And, in turn, the only way to do that is to know how to sort the genuinely useful and impartial labs from those that prove inconsistent or, worse still, have their own interest in the outcome of a supposedly impartial appraisal.

Because we know their grading is reliable and consistent, we will only recommend diamonds certified by GIA or AGS. Contact our experts at Willyou.net for personal care while finding your perfect diamond.  

Buying a diamond with an independent certificate should give you peace of mind knowing that your diamond is equivalent to the quality and value being claimed. With our many years of expertise, we do not believe that the majority of high profile labs operating today are able to provide this assurance. 

We recommend buying only a GIA or AGS-certified diamond. In addition, buy diamonds from reputable sellers who sell diamonds certified by these labs, such as Willyou.net.