IGI VS GIA Vs AGS (Which One Should You Trust)

When you waltz into a diamond store and know for sure, you’re buying a quality product, it gives this aurora—an aurora of confidence. There’s nothing worse than being taken advantage of through your own ignorance.  You need to educate yourself on the difference between each diamond grading laboratory to prevent that from occurring.  

The IGI, GIA, and AGS all serve the same purpose, and that is to grade the quality of the stones at hand. Yet, somehow, there is still a massive variance between these organizations. Specifically, the IGI Vs. the GIA and AGS.  The major variance lies within the IGI.  With loose standards, and a poorly designed SOP, the quality control is rather lacking.  It’s almost a given to scale down a diamond certified by IGI by 2-3 categories. On the other hand GIA and AGS are praised for their honest quality certifications. 

Throughout this article were going to compare and contrast each grading laboratory.  We’ll talk about their backgrounds, their reputations, and which ones are or aren’t trustworthy.  There’s no better way to protect your money than to educate yourself firsthand on who is setting the prices.

The International Gemological Institue The Gemological Institue of America American Gemological Society 
As little as one person will grade a stoneAt least 4 people grade each stoneGem Cut grading system 
High Volume Lower Volume Lower volume
1 level of quality reportGreat reputation4 C’s
$575 for a 7-10 carat test4 C’s2 levels of quality reports available 
Terrible reputation3 levels of quality reports availableMust go through jewler to get a price report
$ 656 for 7- 10 carat testGreat reputation

 Reasons Why Diamond Certification is Necessary

The entire purpose of a diamond certifier is to be a third party in a transaction.  They’re the fair point of view. 

They analyze and estimate the actual cost of the stone, without a biased opinion.  Without this sort of middleman, the average man and jeweler would never be able to come to a deal. Both buyer and seller, have motives to either want the stone to be worth more or worth less. 

A diamond certifier is a person sanctioned by either the IGI, GIA, or AGS, to open source their opinion on the value and worth of each stone.  This process revolves around the concept of the 4 C’s, cut, clarity, color, and carat size.  

The opinion from the certificate of authenticity will be viewed by the consumer, or you. This will be the information you’re directly given to tell you what it is, you’re actually looking at.  The weight, the color grading, size, etc.  

Without integrity in this system, people would be getting scammed left and right, without even knowing.  This is the consumer “insurance policy” or protection from the higher man.  

Not only does this certification matter at the time of purchase, but it also carries after.  It gives confidence in what you purchased. You’re able to evaluate, resell, or hold,  knowing you own what is really written on the certificate.  

The Necessity for Regulating Agencies

It is extremely important for there to be standards and regulations when it comes to diamond certification.  Without regulation on the agencies handing out certificates of authenticity, there would be a monopoly and thousands of mislabeled stones on the market. Having an inaccurate assessment of a diamond puts many people at risk.

The consumer takes the direct effect by buying something that is not as stated.  Once the stone is reevaluated, you’ve lost your money. Most labs are strict and consistent when it comes to setting a standard operating procedure.  Though, some slip through the cracks. The other labs do not have a tight set of standards and are known for being inconsistent.     

With this inconsistency, it’s inevitable for a buyer to purchase the stone at a higher cost. Solely, due to a lack of knowledge. The average person walks into the facility with the belief they’re not going to be taken advantage of. Without these regulations, it would be impossible to purchase a diamond on the open market without a fair standing. 

The IGI, GIA, and AGS are the major certifiers in today’s market, these are the labs we’re going to look into.  

The Major Certification Labs

IGI-International Gemological Institute


The International Gemological Institute is an institute that was founded in 1975.  IGI is headquartered in Antwerp, Belgium, and has offices all over the world.  Notably, NYC, Hong Kong, Mumbai, Los Angeles, and many more.  This institution specializes in diamonds, colored stones, and jewelry. 

Though not one of the most popular gemological certifiers in the world, they are the largest known independent gemological laboratory in the existence. IGI is most known to be certifying stones out of Asia and Europe. 

The IGI services the public through diamond dealers, and jewelry companies worldwide. They provide colored stone reports, and independent grading reports.

They also provide identification, appraisal reports, and diamond authentication. Something they’ve recently started to offer is diamond and colored stone courses through IGI’s Schools of Gemology.  Which on the other hand has been held to a high stature.  


The IGI is known as the cheaper source or the less accurate of all appraisers known today.  They produce a large amount of volume in chains embezzled with diamonds, hence delivering an immense amount of diamond certifications.  By doing this, they’re inflating the market value and creating an inaccurate value of thousands of diamonds.  

Not only does this call upon the reputation of IGI, but it also brings their insurance company to the spotlight.  Although the IGI and their insurance company defend their certifications it is known to be causing problems for clients.  Not only will the client be paying higher for the diamond but also higher on their personal insurance policy.  

This is known information, and it’s a direct impact on IGI.  The company’s ethics and morals are being questioned by all in the industry.  Both GIA and AGS are recognized to stay true to their mission statements and support their customers all the way.  

With this being said it is safe to say you want to steer clear of any jewelers sourcing from IGI. 

GIA-Gemological Institute of America


The Gemological Institute of America was founded in 1931, in the United States of America. Robert M. Shipley, a former jeweler, started the GIA.  As a former jeweler, he held his standards higher than the average man.  He respected the quality of his work and appraisals.

They’re based in Carlsbad, California, and have branches in many cities across the world. Currently, they’re the leading authority in gemmology and a global organization that certifies genuine diamonds.  

The GIA has been controlling the jewelry scene for more than 50 years.  They’re the originator of the 4 C’s system, color, clarity, cut, and carat weight. In 1953, 32 years after being created, they issued their first-ever diamond report.  This report focused on the customer, as no one had ever done before.  


The Gemological Institute of America set a standard to determine the quality of diamonds and gems globally.  The non for profit conducts extensive research to grade and identify genuine diamonds.  Yes, the GIA is an independent non for profit organization.

Through word of mouth and following standards, the GIA has built the repertoire to an impressive level.  They’re the most trusted brand, holding their stones to the highest standards and qualities.  They implement the 4 C’s in all of their authentications and strictly grade for what is in front of them. 

If you’re looking for high-quality jewelry, make sure you go to a jeweler who sources from GIA labs.  This small tip alone will save you thousands of dollars.  

They train all of their employees to a standard higher than the rest. GIA also labels each diamond with a report number, which is laser-inscribed into the diamond. This will match the exact graded diamond, so, further down the road, there is no speculation about where the diamond came from or the quality. 

AGS-American Gem Society


The AGS, or the American Gemology Society, is a notable and reliable diamond-grading organization.  A few years after the GIA was first started, a few jewelers held the same vision as Robert M Shipley.  In 1934 this group of men wanted to be sure every diamond buyer was protected from false advertising and fraud in the diamond industry. 

Currently, the AGS operates its headquarters out of Las Vegas. The AGS offers retailers, jewelers, and private buyers gem information, research, consumer protection, and standard grading of diamonds. With consistent grading and a list of happy customers, the AGS is one of the most trusted labs for grading, globally. 

The AGS grades completely and thoroughly.  When buying diamonds, AGS gives you a grading and description of the diamond you’re buying. It is a complete look for a round brilliant, oval, emerald, princess, and cushion cut diamond.  

By following the 4 C’s system, derived from GIA, they ensure all of their stones are graded appropriately and with honesty. 

The differences between AGS and GIA are the techniques used for measuring Cut quality. AGS uses a cut grading scale from 0-10. 0 meaning perfect and 7-10 meaning low quality. Now when we visit the GIA scale, it includes descriptive words such as excellent, very good, good, fair, and poor.


Roughly 3000 jewelers and agencies trust AGS with their jewels and pieces.  To be able to join the AGS every member must do a peer-reviewed application and complete an annual recertification test.  

Maintaining this system, not only does the AGS community get held to standards it also protects the customer by supplying expert knowledge on all bases around diamonds and gems. 

AGS is known for its many different levels or certifications. These reports are diamond quality reports, gold diamond quality reports, and others. They set themselves further ahead of the competition with even more detail and specifics. 

Differences Between the Certification Labs

The differences between these 3 lab certifications are in their standard procedures, quality tests, and morals.  

The Gemological Institute of America’s reputation is because of how truly independent they are. It is impossible to fake, rig, or fix the grading system.  When dealing with GIA every diamond is viewed by four expert gemologists. Each uses descriptive phrases such as excellent, very good, good, fair, and poor.

The American Gemological Society is a renowned lab and often compares with GIA. The AGS is praised for its scientific approach in cutting grading instead of using alphabets. As aforementioned the grading uses a scale of 0-10 for rating diamonds, with 0 being the best and 10 being the worst. 

 The AGS’s cut measuring system is better and uses robust optical ray tracing. This method measures the shimmer and shine of a diamond. Basically, the cut grading may be the only small break separating AGS from GIA. If you want a more accurate certification in terms of cut, head over to the American Gemological Society. 

The International Gemological Institute is a for-profit organization. They are a major figure in the gem world over in Asia and Europe. They’re known in the United States as well but are used less due to their history.  

Even with its stature and being known globally, do not take it as a shock if you purchase a diamond from them and it’s really 1-3 levels below. Be prepared to pay a hefty figure for lower quality. The IGI uses a color scale, with the value being in letters.  With D being colorless and almost clear up to Z being the yellow tint and yellow-hued stones.   

Which Diamond Certification Lab Should You Trust?

The diamond lab that is held to the highest standard, and has the best reputation is GIA.  They’re known for being meticulous and tedious when certifying any and every stone that leaves their facilities.   They have a rich history, and their founder originated the 4 C’s system which is used so widely today on the market.  Without GIA, the system could be decades behind in diamond certification.  

Their grading system is simple and proven trustworthy. Jewelers send their stones to GIA and receive them back a couple of weeks later with grading certificates. Each stone that is sourced from GIA exuberates confidence in all of their purchasers.  When buying a stone graded by GIA, you know what you’re receiving.  

Even though GIA is our number one pic, AGS is not too far behind them.  AGS has a more sophisticated grading system going specifically for the cuts of each diamond. If accuracy up to the hundredth thousandth is what you are after, then AGS should be the choice for you.

IGI is last on our list for quite a few reasons. The integrity and ethics of IGI have been corrupted by the monopoly of the jeweler industry.  They’re focused on numbers and making money instead of being the middleman for the common man.  If you buy a diamond sourced from IGI be prepared to overpay and lose quality.