IGI vs GIA vs AGS: Our Diamond Grading Laboratory Guidebook
When you start off on your diamond shopping adventure, you’ll often hear jewelry retailers talking about gemological laboratories (namely the Gemological Institute of America and the International Gemological Institute, among others) like they’re some sacred, esoteric halls of all knowledge.
Their gospel — set out in official, color-coded grading reports and industry newsletters — is the source of diamond values across the entire world.
The GIA is generally considered the gold standard for diamond grading in the industry, but did you know that there are other major gem labs as well? Surprisingly, not all of these laboratories function in the same way. Some are more lenient with their grading standards than others, and some even use completely different sets of criteria. And with acronyms like IGI vs GIA vs AGS, they don’t make it easy to distinguish between labs!
How do you know which diamond certificates are trustworthy? Which one should you choose when you need a grading report for your diamond? Let’s learn about some of the major players of the fine jewelry industry.
A Brief History of Gem Labs
Diamond jewelry has been around a lot longer than diamond grading reports. Up until about a hundred years ago, fine jewelry was sold with absolutely no standardization from one jeweler to another. Sellers came up with their own descriptions and benchmarks for what made a beautiful and valuable diamond — sometimes making it up as they went along — and a consumer had no way of knowing what sort of value they were getting for their money.
Obviously, this was problematic.
This all changed with an American man named Robert M. Shipley. After an early career working as a jewelry seller, Shipley realized how little he really knew about gemology. He took it on himself to learn everything he could about the industry (a man who admits when he’s wrong and then goes out to try and learn more?! swoon.).
In 1931, Shipley founded the Gemological Institute of America as a way to share that knowledge with others. Originally an educational institute (a tradition the GIA carries on today), it wasn’t until the 1950s that they began releasing their globally accepted diamond certificates.
Since then, several other gemological laboratories have risen to prominence and made their own contributions to the fine jewelry industry. The European Gemological Laboratory (EGL) opened in 1974 and the International Gemological Institute (IGI) in 1975, both originating in Belgium before spreading to other parts of the world.
The American Gem Society, originally established in the 1930s by that same Mr. Shipley as a guild for jewelry professionals, publicly launched their gem grading laboratory in 1996. The International Gem Society followed in 1998, and then the De Beers-backed International Institute of Diamond Grading and Research was created in 2008.
Is that enough acronyms to keep track of, or what?! Read on for a quick overview of the major gem labs that remain relevant in the industry today.
An Overview of Diamond Grading Labs
The Gemological Institute of America (GIA) is irrefutably the most prominent, trusted gemological laboratory in the world. They operate primarily as a non-profit educational institution, which means that they don’t benefit from financial relationships with gem dealers or retailers. This is super important because, unlike some other gem labs, they don’t artificially inflate their diamond assessments to the detriment of consumers.
Operating out of thirteen countries, the GIA has a presence all over the world and is the lab you’ll see most commonly used by reputable jewelry stores. GIA-certified diamonds tend to sell at a premium because their assessments are the most trusted across the jewelry market. They’re also responsible for creating the 4 Cs system that’s still in use today.
The American Gem Society (AGS), originally created as a jeweler’s guild in the 1930s, is another major reputable gem laboratory. They’re interesting because they have created their own grading system completely separate from the widely used system started by the GIA. Instead of an alphabetized system (D-Z for color, F-I3 for clarity), AGS uses a numerical system of 1-10.
In particular, the AGS is known to be much more stringent in regards to cut grading diamonds. They developed the “ideal” cut grade for only the very best diamonds, and they offer cut grades for a wider range of alternative diamond shapes than the GIA, who only cut grades round brilliant diamonds.
The International Gemological Institute (IGI) is a worldwide gemological laboratory that’s come under intense scrutiny for its overly inflated diamond reports. They cater to major retailers like Walmart and Zales, supplying them with lab reports for the diamonds they sell.
However, their close relationship with these retailers is not in the consumer’s best interest – the backing of these certified diamond reports allows the seller to overcharge for a lower quality diamond, the insurance companies benefit by charging higher premiums for the perceived value, and the partnership gives the laboratory a steady, reliable stream of work. Everybody wins… except you.
While some subjectivity is to be expected when diamonds are graded by real human beings, it’s been proven more than once that the systems used by IGI are fluctuating and unstandardized.
The European Gemological Laboratory (EGL) has a presence in Europe, the United States, and Canada, though their reputation has steadily plummeted in the fine jewelry market. Like the IGI, they’ve been accused of inflating their grading reports and catering to the interests of dealers rather than consumers. This has caused the EGL to be the focus of several high-profile lawsuits.
Rather than being an education-based institution like the GIA or AGS, EGL is a for-profit business whose goal is to help diamond dealers sell their jewelry for the highest price. In the 1990s they also introduced the controversial SI3 clarity grade, which has made a lot of industry professionals very angry.
Be very cautious when looking at diamonds accompanied by a certification from this laboratory.
De Beers Group Industry
Formerly the International Institute of Diamond Grading & Research (IIDGR), this lab has been around since 2008 as a testing center for De Beers diamonds. They later expanded to offer industry-wide testing in the UK, Belgium, and India exclusively for natural, untreated diamonds. In 2017 they launched a gemology education program and in 2019 rebranded their gem lab from the IIDGR to De Beers Group Industry Services.
With generations of expertise, this gem lab seems to be an honest and reputable choice. However, it is still relatively unknown in the jewelry industry as a grading laboratory.
HRD stands for Hoge Raad voor Diamant, or Diamond High Council. Relatively unknown in the United States, this Belgian gem lab is a major player in the European market. They use the standard D-Z color scale and grade the clarity of their diamonds from LC (loupe-clean) to P3 (Piqué, or Included).
Unfortunately, they fall into the same pitfalls as many other up-and-coming gemological laboratories: broad and inconsistent grading parameters that aren’t industry regulated. While they grade more tightly than labs like IGI and EGL, HRD still hasn’t reached the same reputation for reliable, reputable gem grading as the GIA.
The Swiss Gemological Institute, or Schweizerische Stiftung für Edelstein-Forschung, is a leading European gem lab. Much like the GIA, it is a not-for-profit institution that offers online gemology courses and regularly contributes to the advancement of the jewelry industry. While still on the rise in the United States, this laboratory is growing in reputation as a reliable, reputable source of gem grading.
Switzerland-based Gübelin is a well-known laboratory that specializes in grading colored gemstones. They’ve been around since 1923 as a jewelry retailer, but it wasn’t until much later that they became a fully independent grading service. While they do grade diamonds and pearls, they’re mostly associated for their studies on colored stones. Their precise, standardized rating system for these gems that is making its way into the international jewelry market.
While this laboratory is reputable and recognized in Europe, their system is still quite new and might not hold a lot of weight for resale and insurance purposes.
Do You Need a Diamond Certificate?
Here’s the big-ticket question: do you need a diamond grading report sitting in a drawer in order to wear and enjoy your diamond jewelry?
Well, not really.
But even if you don’t take it out and look at it every day, there will certainly be times in your life when you’ll be very glad you have one.
A diamond certificate — sometimes called a diamond grading report or a diamond dossier — is essentially an identification card for your unique diamond. In the event that your jewelry is lost or stolen, or if you want to resell it at a later date, or if you ever need to prove ownership of your stone, this document has all the information.
A diamond report will list the following diamond characteristics:
- carat weight
- distinguishing features
- color grade
- clarity grade
- cut grade
It may also list:
- geological origin, if known
- any treatments that have been done (such as color treating)
A diamond report shows why and how your diamond is a one-of-a-kind individual.
It is not the same as a diamond appraisal. Unlike a jewelry appraisal which lists a piece’s financial value for insurance or resale purposes, a diamond report does not talk about money. It is simply an identifying blueprint of what makes your diamond unique and beautiful.
It never hurts to have both a grading report and an appraisal — you can read about why an appraisal is always a good idea.
Diamond Certification FAQs
What’s the best place to get my diamond certified?
Across the entire market, the GIA consistently comes out as the most reliable, trustworthy laboratory for diamond and gem evaluations. Most reputable jewelers use GIA services, even though — or maybe because — they prioritize transparency for the consumer over profit for the dealer. It’s also the most globally accepted form of documentation if you ever want to resell your diamond in the future. The GIA is honest, consistent, and maintains high standards for their diamond grading.
AGS is another gem lab that has a reputation for being consistently reliable. However, their grading system is a one-off that can be difficult to translate when selling or getting insurance valuations, as not everyone is as familiar with it as they are with the GIA-founded “4 Cs”. The AGS also isn’t very well recognized in Europe. Within Europe, we recommend GIA or the SSEF.
Why don’t my diamond reports match?
If you end up with two (or more) diamond reports — maybe you wanted a second opinion other than the one provided with your purchase, or maybe one is a more recent update since the one you’ve had for years — you may be surprised to see that the information on the reports doesn’t quite match up even though they’re talking about the exact same stone. What gives?
As we’ve seen, some gem labs grade more stringently than others, and some lean upon their grades in order to benefit the retailer, who is their primary customer. A stone that the GIA grades as G color VS2 might be graded as J color VVS1 by a lab like IGI or EGL. This is why it’s so important to work only with trustworthy, ethical gemological laboratories like the GIA or AGS.
Another thing to remember is that despite being meticulously trained scientists with years of industry experience, gem graders are still human beings. A gemologist who had a horrendous sleep because they just broke up with their boyfriend might be harsher on a diamond than one who slept in and had pancakes for breakfast. Most gem laboratories will have their stones graded by several gemologists, and then take an average of all responses submitted. However, there is still a small acceptable margin for subjectivity in this process — this is called “tolerance”.
How much does a diamond certification cost?
Generally the cost for a diamond certificate depends on the carat weight of the stone. For GIA grading, reports start at around $50 and can go into the thousands for stones of spectacular sizes. There are also add-on services such as custom, microscopic laser inscriptions (how cool is that), and detailed geological analyses. Then there are shipping and insurance costs, but these will usually be lower if you submit it to the GIA yourself rather than going through a jeweler.
European labs tend to charge a bit more, with prices for the SSEF starting at around $300 and increasing from there.
What’s the difference between diamond certification and appraisal?
Diamond certification — also called a diamond grading report — is a detailed analysis of the diamond’s quality and distinguishing features including its color grade, carat weight, cut grade, clarity grade, and notable blemishes or inclusions that contribute to the clarity grade. A diamond certification may also list any treatments or enhancements used on the stone, and sometimes its geographical origin. The report does not list any monetary values including the retail price paid, the resale value, or the replacement value.
An appraisal, by contrast, comes down to monetary value — either for insurance purposes (replacement value) or to sell (resale value). It will usually include major distinguishing characteristics and a simplified version of the stone’s grading information.
Because the prices of diamonds fluctuate, it’s recommended to renew an appraisal every five years. The individual diamond will never change, though, so the diamond’s grading certificate should be relevant for life.
What about colored gemstones?
Many gemological laboratories grade both diamonds and colored stones, though some labs will specialize in only one or the other. The GIA and SSEF grade both colored stones and diamonds.
AGS focuses only on diamond grading. Gübelin, a European gem lab, does both but is particularly renowned for its work on colored stones.
If you’re looking to have a colored gemstone evaluated, make sure you look through the services offered by the gem lab and see what sort of grading certificate they offer. GIA and SSEF both come highly recommended.
Do gem labs grade pearls too?
Yes! Pearls are a little bit more niche than diamonds or colored gemstones such as rubies, sapphires, and emeralds. However, they’re a very important part of our jewelry heritage and many gem labs such as GIA and SSEF do offer pearl grading services.
Which gem lab has the best educational resources?
The Gemological Institute of America is absolutely the highest industry-recognized source of scientific gemological training. They offer a full graduate gemologist diploma as well as specialized diplomas in diamonds, pearls, and colored gemstones. SSEF and Gübelin both offer short courses in fine jewelry training.
The Bottom Line
With gemological education becoming more and more accessible, new gem grading labs are opening up all the time. You could practically put your hand into a bag of Scrabble tiles and come up with an acronym for someone’s diamond grading laboratory.
However, the combination of conflicting financial interests and a lack of real-world experience means that many of these labs are inconsistent at best, and dishonest at worst.
For reliable, consistent, trustworthy certification of your diamond jewelry we recommend the GIA worldwide, or AGS if you’re in the United States, and SSEF if you’re in Europe.
For colored gemstones and pearls, GIA, SSEF, and Gübelin are all reputable choices.
All the best in your hunt for diamond certification!
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What about AGA? It’s in the title but I can’t find it mentioned in the article.
This should have read “AGS”. Updated.