How to Certify Your Diamond – A Step-By-Step Guide

You’re a smart buyer. You know that a good deal balances price and value. But what if you don’t know the value? You consult the experts! In this case, the diamond experts. Are you wondering how to certify your diamond?

Certification labs can help you with a little something called diamond certification. How is a diamond certified and is the process right for your diamond? Come along and we’ll answer all your questions about the process.

What is Diamond Certification?

A diamond certificate is an official report describing the diamond’s quality. They come from independently-operated labs, meaning there’s no bias involved. Certificates are also called “grading reports.”

Okay, so what are they used for? They can help determine the actual value based on a ranking of each quality. It won’t change the diamond’s worth, but it can help to assure the price accurately reflects it.

How To Certify Your Diamond

Most diamond certifications come from one of four labs: 

  • GIA (Gemological Institute of America)
  • AGS (American Gem Society)
  • IGI (International Gemological Institute)
  • GCAL (Gem Certification and Assurance Lab)

We’ll get into who they are in a bit. For now, let’s look at how to certify your diamond through a lab.

First, they clean the diamond for any dust and take its weight in carats. Carat weight is the only objective measurement. The rest of it depends on the gemologist’s professional opinion.

The lab grades for the diamond’s color next. Or rather, how colorless it is. This grade is like a report card with a slightly different letter system: D (highest) to Z (lowest.)

Clarity is the next step. Under a microscope, the lab searches for inclusions and blemishes—internal and external marks. Some labs will make a map of this, too. 

Finally, let’s examine the cut. A computer takes a scan of the stone and measures every facet. These numbers get averaged, and the grade depends on what category it falls under, also based on the lab.

But remember, grades are subjective. Which lab can you trust? Looks like a side-by-side comparison is in store to help you find the right lab! 

Where to Get Your Diamond Certificate

There’s no universal system for grading, so a lab’s reputation is critical. There are several popular labs, and we’ll list each one below.

GIA – Gemological Institute of America

GIA is the industry’s gold standard, and for a good reason! They have strict standards, high-end equipment, and a research-oriented approach. Lots of labs even say they “grade like GIA” to assure quality. One such lab is AGS.

Visit GIA

AGS – American Gem Society

AGS is true to their word when comparing themselves to GIA. With similar standards and well-respected cut grades, AGS is a great choice. The only difference between these two is some minor wording changes in ratings.

Visit AGS

IGI – International Gemological Institute

This is where the standard lowers a bit. While IGI is a frontrunner for grading lab diamonds, their grades aren’t 100% reliable. They have a reputation for “upgrading” diamonds.

It sounds like a boost, but sadly, it’s not that kind of upgrade. “Upgrading” means the grade given is higher than the actual grade of the diamond. This means the price is higher than its worth.

Visit IGI

GCAL – Gem Certification and Assurance Lab

GCAL kicks the standard back up a notch; they’re younger than other labs, but their grades are more consistent with GIA. Their reports are thorough and even include an optical light performance rating.

They also provide a Gemprint of your diamond in case it goes missing. This might also get you a discount on insurance for it! The only drawback? They aren’t as well-established as labs like GIA or AGS. We’d still recommend GIA or AGS as your first choice.

Visit GCAL

Of course, quality is essential, but budget matters. Before deciding where to certify, let’s make sure you know how much you’ll be spending.

how to certify your diamond

How Much Does A Diamond Certification Cost?

The cost of certifying a diamond mostly depends on its weight (in carats) and the lab doing it. On average, it’ll be about $150, but a few factors can change the price.

The Diamond’s Weight

The lighter a diamond is, the cheaper the certification report. At GIA, a full report for a 0.5-carat diamond is about $64, while a 1-carat is about $105. 

How Extensive the Report Is

We’ll keep the GIA example going. They offer three kinds of reports, each at different prices. How different are we talking here? Well, the more extensive, the more expensive. 

Other labs like IGI offer both their reports at the same price, but they aren’t as reputable as GIA or AGS. Keep that in mind for decision time.

Sending It Through a Jeweler

Most labs will accept diamonds from individuals and jewelers. Some labs, like AGS, only take them from jewelers. The price can almost double when you choose the jeweler option, but don’t think it’s just a money grab. Jewelers and labs have established partnerships, for one. You’ll also avoid the hassle of shipping and have insurance if the stone gets lost in transit.

Added Features

The main feature to consider is laser inscription. Getting the report number inscribed on the diamond is vital for selling because it matches your diamond to its report. It’s also microscopic, so you won’t even know it’s there.

You can probably already tell that your certificate will have lots of info, so let’s break down what you’ll see.

how to certify your diamond

Reading Your Diamond Certificate

Fortunately, you don’t have to be a gemologist to read your certificate. Let’s use GIA’s as a guide, which includes the report number, and the all-important 4C’s of diamond grading.

Report Number (or Reference Number)

You can think of this as a social security number. Lose your paperwork? Need to verify your stone is the real deal? The lab keeps your report number in their database, so it’s as simple as going on the website or contacting them for a replacement. 

The 4 C’s (Carat, Color, Clarity, Cut)

Every diamond lover’s favorite! We’ve discussed carat, but let’s explore the other 3C’s that influence a diamond’s value.


You know by now that carat weight is objective, so this number is consistent. 


For color, we can divide up the D-Z scale. 

  • D-F: rare and extremely valuable
  • G-J: still colorless, balancing quality and price
  • K-Z: visible coloration/flaws


The clarity scale correlates to a diamond’s sparkle, which we love! Any rating between FL (Flawless) to VS2 (Very Slightly Included) is good news. The inclusions, if any, aren’t visible. An SI or I at the beginning, means lower brightness and durability.


The cut grade has a much simpler scale, from Excellent to Poor. If clarity ratings have you confused, don’t worry. The cut rating is another indicator of brightness and sparkle.

Can You Sell A Diamond Without A Certificate?

If you’re in a pinch and need to know how to certify your diamond quickly, one way is selling to a jeweler that grades diamonds. Or you could get a diamond appraisal instead of a certification. This will give you the estimated market price, which a (reliable) certification won’t.

The more important question: should you sell (or buy) a diamond without certifying? Certainly not. A certificate ensures you’re getting the best price for the diamond’s value.

Do Your Diamond Justice 

If there’s one thing you’ve learned about a diamond certification, it’s that diamonds are an investment. Depending on your budget, a certification might be, too. As Ben Franklin said, “An investment in knowledge pays the best interest.” 

Now that you know how to certify your diamond, you can feel confident about buying or selling one. After all, peace of mind is priceless!




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