Diamond Certification: The Need For Certified Diamonds

Last Updated on August 29, 2023 by Juli "Jewels" Church

Wondering about diamond certification?

You're in the right place.

In this Learning Guide, I'll compare different diamond grading labs as well as answer questions like:

diamond certification
  • Why is Diamond Certification Important?
  • What's the Best Grading Report?
  • Do Lab Grown Diamonds Need Certification?

What is Diamond Certification?

It surprises me how many people who own a diamond engagement ring don't know about diamond certifications or grading reports.

But let me tell you a secret.

Many brick and mortar retailers won't tell you about them either. In fact, as a former Kay employee, we only had maybe 15 out of 120 certified diamond rings.

My boss had told me that it wasn't a necessary thing, but to always try to push them because they're more expensive. But she never really explained what they were.

I didn't learn about diamond certs until after. I didn't learn majority of my gemstone education until after I left the retail scene.

In places like Kay and Zales, they only care about what makes the sale goal, not giving you actual diamond education. Their employees don't even get it, why would they give that info to customers?

Fortunately, you have me.

When you purchase a certified diamond it comes either a digital or printed card called a diamond certificate or a diamond grading report.

Diamond certificates come from different gemological laboratories in the jewelry industry. Some labs may have different nuances on a grading report, but overall they list the same key information.

The average diamond certificate will most often tell you these details about your loose diamond:

  • Diamond Shape
  • Diamond Cut Grade
  • Diamond Color Grade
  • Diamond Clarity Grade
  • Carat Weight
  • Polish
  • Symmetry
  • Proportions
  • Measurements
  • Fluorescence
  • Treatments
  • Diamond Plot
  • Grading Scales
  • Laser Inscription

A lab grown diamond report might tell you which creation process was used in production.

Do You Need Certified Diamonds?

You might be wondering if you need a certified diamond? After all, it's more expensive than a non certified diamond. And let's be honest, diamonds cost enough.

Not every diamond you own needs to be certified. Generally, only loose diamonds or solitaire engagement rings have certified diamonds. Side diamonds, pave diamonds, and melee diamonds don't need to be certified.

If you have a cluster center, your diamond won't come with a grading report. Cluster settings are made of small diamonds set close together to appear as one stone from far away.

Here's why you should buy diamonds with certification.

A Certified Diamond Ensures You Get What You Pay For

Before you buy a diamond, you should make sure you have a general understanding about diamond quality. The price of a natural diamond is dependent on its quality and diamond grades.

For some, buying a diamond is a careful process. For others, not so much. Many people hit up their local mall jeweler and get sold a diamond ring they know nothing about.

But for the sake of argument, let’s say you did your research and know all about the 4Cs. You picked high clarity and color grades on a 1 carat diamond

How would you feel if you brought that diamond to a leading authority and found out the diamond didn't have the grades you paid for? In fact, they were 1-2 levels below what you thought you were paying for.

I imagine you'd feel kind'a ripped off, right?

Diamond certification ensures the diamond you're buying has the same grades as noted on the report by the grading lab.

Not Every Diamond Certification is the Same

Diamond certification is not enough. You want to have the right diamond certifying authority for your diamond. The ones listed in this guide are the most common reports you'll find in the industry. 

That doesn't mean they're all reputable. 

The biggest thing you want in a grading lab is consistent grading. Diamond grading is not an exact science. All reports have a disclaimer about that. 

Even if you're trained in diamond grading, people's eyesight are different. One person may see a yellow tint more than another. So it's possible for mistakes to be made, or have to give it a general consensus of a team. 

What you want to look at is how often this happens with their diamonds. There are reports online of people testing grading strictness from various labs. Some authorities grade lower than others. Some have graded the same diamond twice, and given them different grades. 

What are the Different Types of Diamond Certifications?

GIA Certification

The Gemological Institute of America is the world’s leading authority on diamonds and fine jewelry. They are the first to know anything about gemstones and share their research with the public. 

The GIA is a good choice for diamond certification because they’re an impartial judge, not attached to any retailer. All different brands sell GIA certified diamonds. 

This grading lab is known for having the strictest guidelines when grading diamonds. Each diamond is matched to a master pair of graded diamonds by multiple GIA gemologists within the company. 

GIA diamonds will have their report number inscribed on the girdle (edge) of the diamond. The GIA gives the cut grade Excellent Cut instead of Ideal Cut. Only round diamonds are given a cut grade, despite retailers sorting fancy shapes into categories. 

gia report

The American Gem Society is another popular grading lab. They are considered equal in standard to GIA certification, but not as common. 

The biggest thing about AGS diamonds is that they mainly grade round diamonds. The AGS is known for their special cut grades. The AGS cut grading scale doesn’t follow the traditional Excellent, Very Good, Good, etc. like the other grading labs on this list. 

That’s because the AGS grades their cut based on a 0-9 scale, with 0 being the highest. Instead of having an Excellent Cut diamond, the AGS hands out AGS 0 Ideal diamonds. 

The American Gem Society is a reliable grading lab to get a diamond certification from. They are trusted and respected. They’re just a little harder to find than other certificates.

ags natural diamond report

The International Gemological Institute is one of the most popular diamond certifications you’ll see online. They used to be the leading independent lab for brick and mortar jewelry stores, but now they have a heavier presence online. 

One of the reasons retailers choose IGI certified diamonds is because they can get them quickly and for a good price. When it comes to local chain stores like Jared and Kays, they’re more interested in bulk prices than individual standards. 

You’d think with as many IGI diamonds as there are  on the market, they’d be a reliable lab. However, this isn’t the case. At least, not with a natural diamond. The grading reports for an IGI lab grown diamond is good, but the earth made diamonds have inconsistent grading. 

igi natural diamond report

EGL Certification

The European Gemological Laboratory is obviously based in Europe, but you can find them around the world. Unfortunately, these aren’t very reliable, despite their claims. 

Overall, there are heavy inconsistencies in color and clarity grades. In all fairness, these are the most difficult to grade with objectivity. Over testing, it’s been said that EGL certificates are scoring 1-3 grades below what the GIA is grading them as. 

People might be drawn to EGL certificates initially because they come across as such a good deal compared to other diamond certifications. They may cost less upfront, but you could very well be overpaying for lesser quality.  

EGL USA natural diamond report


The Hoge Raad voor Diamant is one of the big grading labs in Europe. They are based in Antwerp, Russia. The name translates to the High Diamond Council. 

This grading lab continuously claims to be world renown in its diamond grading, but they’re not common outside Europe. The likelihood of finding an HRD report in a retailer store isn’t very high. 

In fact, it’s been said that HRD certified diamonds sometimes come out more expensive than GIA certified diamonds. That alone would deter many. 

People familiar with other grading reports might be a little confused when looking at an HRD report for an I clarity diamond. That’s because HRD uses a different term for I clarity grades. Instead, they call it P1, P2, and P3. The P is for pique. Essentially, it’s the same as I1, I2, and I3 clarity. 



Remember how I said IGI used to be the primary grading lab for mall chain retailers? Well, the Gem Science International lab are the ones who have taken their spot. IGI went off to be more selective about who they provided graded diamonds to, so GSI came into the picture. 

Unlike the IGI certs, GSI hasn’t been around for long. They were established in 2005. They’re the only big grading lab established in this century. And who do they cater to, but Jared, Kays, and Zales. 

Some of the best diamonds at these stores come with GSi certificates. My Tolkowsky engagement ring came with a GSI report, show below: 

I’m betting that if I sent my ring off to a different lab for grading, it’d come out different. 

GSI Grading Report

Independently Certified by GIA Gemologist

You might run into engagement rings or diamonds that are labeled as “independently certified by a GIA Gemologist. Let me clarify what this means, because the wording is a little misleading-intentionally. 

Not only is the GIA the hub for diamond and gemstone research, it’s also a school for gems and minerals. Their biggest program is the Graduate Gemologist program. It’s the highest achievement one can receive in the jewelry industry. 

You have to pass a diamond grading exam in order to receive that diploma. However, this is only a small portion of the entire program. Not everyone that graduates from the GIA specializes in diamond grading. 

So when a retailer specifically says their diamonds are certified by a GIA gemologist, it’s someone who obtained the diploma. Graduates from the GIA aren’t affiliated with the grading lab. It doesn’t mean they are a certified diamond grader. There are many jewelry careers to go within the GG degree. 

In House Certification

If a diamond  has in-house certification, it usually means one of two things. A) They might have the GIA gemologist like mentioned above, or the company may produce their own certificates under another educated employee. 

If we’re talking about lab grown diamonds, there are some production companies that create their own certificates as well. Diamond Foundry is a popular one. 

How Much Is A Certified Diamond?

Certified diamonds in a retailer’s inventory won’t tell you how much the diamond certificate costs. The cost is factored into the price of the diamond ring. 

Alternatively, you can send an unmounted diamond directly to a grading lab to have it certified. Some places can also inscribe your diamond if it doesn’t have one. 

Each grading authority has their own fees for certifying diamonds. Some may display it on their website while others require to inquire within. 

What is the Best Diamond Certificate?

Overall, I’d say the best diamond grading lab is going to be the GIA grading report. It shouldn’t be much of a surprise since they’re at the top of the food chain in the diamond industry. 

However, AGS diamond certificates are reliable as well. You’re just less likely to find them. Many diamond retailers only sell GIA or AGS certified diamonds. 

I also say GIA is preferable because they make it easier to resell or upgrade across retailers. There are some places that will only buy back diamonds with GIA certificates. 

For example, if I wanted to take advantage of Blue Nile’s partnership with CIRCA for selling my diamond, I’d have to get it GIA certified in order to sell it. It’s doable, but kind of a pain. If I already had the best grading report, I’d be able to do it right then. 


There are so many different things to know when buying diamonds. And like your diamond grades, diamond certification is just as important. A grading report or certification lets you know the grades you are choosing are as accurate as possible. 

The best way to ensure your diamond has the most accurate grading labs: The Gemological Institute of America and The American Gem Society. 

That being said, these are the recommended diamond certifications for natural diamonds. For laboratory grown diamonds, there are different approved diamond certifications.

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