What Is “GIA Certification”? The Ins and Outs of a GIA Diamond Grading Report

Buying diamonds that are “certifiably” beautiful...

Diamond imperfections can impact both sparkle and durability, and it’s important to purchase a quality stone that can withstand daily wear for your engagement ring. Luckily, a diamond with GIA “certification” and a clear grading report can protect your investment! But, what exactly does “GIA certification” mean? And what does a GIA diamond grading report entail?🤔

Let’s take a closer look at:

  • “GIA certification” and related terms
  • GIA diamond grading reports and what they mean
  • AGS vs. GIA diamond grading reports
  • The benefits of a GIA diamond grading report

An introduction to the GIA

Logo of the Gemological Institute of America (GIA)

It goes without saying that GIA diamond grading reports come from the Gemological Institute of America (GIA)—the leading authority on diamond grading and inspection. The organization was established in 1931 by Robert Shipley, a businessman who hoped to professionalize the jewelry industry through education.

Before long, Robert Shipley created the “Certified Gemologist” program, which offered classes for jewelry professionals. What started as an endeavor to restore the nation’s trust in jewelry salespeople became a global initiative to train and certify diamond experts around the globe!

The 4Cs

Besides education resources and programs, one of the greatest innovations to arise from the GIA is the 4Cs. Created in the 1940s, these four criteria—Cut, Color, Clarity, and Carat—are the building blocks of diamond grading.

These criteria are now the global standard for diamond grading, bringing together diamond experts worldwide with a straightforward, efficient process for judging a diamond’s sparkle. And all of this information can be found in a diamond’s GIA grading report!

What do “GIA certification” and related terms mean?

When reading the paperwork that comes with a diamond, there are several terms that can seem confusing. Here’s a breakdown of GIA diamond certification and common terminology used in diamond grading:

GIA certification/certificate

Saying a diamond has “GIA certification” is a misnomer, as the GIA doesn’t “certify” diamonds.⚠️ However, they do provide grades for the finer details of a diamond’s color, cut, clarity, and carat. Consequently, many retailers state a diamond has “GIA certification” when it bears a GIA grade.

Similarly, the GIA does not issue “certificates” for diamonds, but they do include diamond specs in the grading report.

To say the GIA offers diamond “certification” would imply each stone has gone through an independent, third-party review. In reality, this isn’t the case, and skilled GIA professionals award diamonds their grades. This is an important distinction that the Federal Trade Commission (FTC) recommends buyers pay close attention to!

As such, just understand that many sellers use the term “GIA certification” to promote their product and suggest their gemstones have documentation to verify their quality. They’re most likely saying they have diamond grading reports, but there is no paperwork that “certifies'' your diamond!🔔

GIA certified diamond

Again we shall say it: the GIA doesn’t “certify” diamonds. However, GIA experts DO meticulously grade diamonds in their lab via rigorous testing and inspection.

So, when you see the words “GIA certified”, you’re likely shopping at a retailer who offers GIA GRADED diamonds. Retailers offering GIA-certified diamonds are promising well-reviewed gemstones, and they should be ready to share the diamond report with you to verify all of the details mentioned above.

GIA diamond report

GIA Certification | GIA Diamond Grading Report

The GIA diamond report is the series of documentation provided with any diamond graded by the GIA.

As mentioned above, the GIA grades diamonds on every aspect of color, cut, clarity, carat, and more. In addition to the proper measurements and grades, the GIA grading report also includes a “diamond plot” or a map of all inclusions and blemishes on or within your chosen stone.

In truth, the GIA diamond report is one of the most respected documents in diamond buying. The paperwork for each diamond is like its ID, detailing all of its identifying information in one place!🏆

Studying the GIA diamond grading report

The GIA provides a grading report with every diamond they inspect! Let’s dive into the GIA diamond grades, the grading report, and other related topics:

How does the GIA grade a diamond? What makes a GIA grade so special?

There are multiple checks and balances that make the GIA grading process an exact, reliable measure of a diamond’s quality. Here’s what goes into grading a GIA diamond:


At GIA labs, all diamonds are stored in their own transparent cases with custom barcodes for identification and tracking purposes. Additionally, all client information is masked throughout the process as well as in the software system graders use to log their findings.

By removing ownership information from diamonds, lab professionals can designate impartial grades to each stone without external bias.

Scrupulous Inspection and Handling Procedures

As diamonds travel through a GIA lab, they are handled with incredible care to guarantee they are not damaged. This includes all steps in the grading process as well as during shipping back to the client!

Careful Measurements

Weight and measurements are a crucial part of the diamond grading process. As such, The GIA only uses electronic micro-balances to weigh diamonds. These balances are incredibly precise, and they weigh diamonds to the fifth decimal place.

For facets, angles, and all other proportions, graders use an optical measuring device to make sure they’re getting the most exact numbers possible.

Diamond Tested

Before a diamond’s 4Cs are graded, GIA experts must test each stone with a GIA DiamondCheck device. This instrument can tell whether a stone is a natural diamond or not, and it can even detect whether the gem has been treated in some way. Furthermore, it can identify lab-grown diamonds, which is a designation that appears on a diamond grading report.

Grading Color

GIA DiamondDock®
GIA DiamondDock® for D-Z diamond color grading

Each diamond’s color is evaluated independently against a standardized white background. Proper light sources are also implemented for easy identification of yellowish hues within each stone.

All color graders must submit their findings individually into the GIA’s software system. What’s more, each diamond does not receive just one opinion, but rather its grade consists of several opinions from a team of independent graders. Once there are enough agreeing opinions, that color grade is assigned to the diamond.

Grading Clarity

Clarity and finish grades actually require multiple rounds of independent graders examining each diamond! First, they inspect the stone with 10x magnification under standard viewing conditions to locate any signs of laser drilling, treatments, fillings, or other clarity/finish characteristics.

Simultaneously, the grader will enter their opinion of the diamond’s polish, symmetry, and overall clarity into the system. He or she will then choose a diamond plot to map out all of the imperfections they’ve encountered.

Next, the grader must verify the diamond’s weight and measurements as well as indicate the state of the stone’s culet and girdle thickness. Once this is done, the diamond may be double or triple-checked, and additional inspections by more experienced gemologists may be necessary to achieve the right amount of agreeing opinions to assign a grade.

Grading Cut

Graders utilize a diamond’s proportions as well as its polish and symmetry notes to designate a cut grade. This final step also accounts for the diamond's fire, brilliance, and scintillation, and its weight ratio and durability also make an appearance in these calculations.

Are there different types of GIA diamond reports?

There are actually FIVE different GIA grading documents available for diamonds! However, we’ll break down the two most common reports below: the GIA Diamond Grading Report and the GIA Diamond Dossier.

GIA Diamond Grading Report

The GIA diamond grading report includes every detail you could possibly need regarding your diamond’s grades. This document is available for every diamond inspected by the GIA in the D-Z color range, and it has a full quality analysis of each grade and related criteria.

The GIA diamond grading report also includes a diamond plot, so you can see the location of any inclusions and blemishes. The diamond plot also lists proportions as well as GIA grading scales.

GIA Diamond Dossier

The GIA diamond dossier is basically a “lite” version of the diamond grading report! It includes all of the quality analysis details of the grading report, but it does NOT have a diamond plot.

Unlike the grading report, a diamond dossier doesn’t come with every diamond in the D-Z color range. Instead, diamonds that are 0.15-1.99 carats are issued a dossier. However, all diamonds that receive a dossier are also laser inscribed and are noted in the GIA inspection registry.

What information does a GIA report include?

A GIA diamond grading report provides a wealth of information about your diamond! The details listed in a diamond grading report include:

  • Cut and shape information
  • Measurements/proportions for facets and angles
  • Color, clarity, and cut grades
  • Carat weight and related ratios
  • Polish and symmetry assessments
  • Fluorescence 

Let’s look at an example to see where you can find important info! This is a real GIA diamond grading report below.

GIA Diamond Grading Report Sample

We’ll divide this section by page:

First page (far left)

This page is reserved for the finer details of your diamond. At the top, the “GIA Diamond Grading Report” section lists the date of your stone’s inspection, the report number, the gem’s shape and cutting style, and its measurements.

Then, the “Grading Results” section notes the diamond’s carat weight, color and clarity grades, and its overall cut grade. Finally, the last section, “Additional Grading Information”, includes polish and symmetry grades as well as information regarding your diamond’s fluorescence.

This last section is also where you’ll find additional comments and info regarding any inscriptions or potential stable treatments your diamond may have.

Second page (center)

The center of your GIA diamond grading report is where you’ll find the diamond plot. This section usually has two different diagrams: one for “Proportions” that includes your stone’s relevant measurements and another for “Characteristics” or any inclusions/blemishes.

Third page (far right)

The third page of your GIA diamond grading report is more for reference, as it includes the full scales used to grade diamonds for color, clarity, and cut. However, it’s an excellent tool for understanding where your diamond falls on the larger scale of each diamond grading criterion!

GIA vs. AGS diamond reports

Another document well-respected in the diamond industry is the report provided for diamonds graded by the American Gem Society (AGS). Similar to the GIA diamond report, the AGS grades diamonds with strict criteria, but their process and requirements are slightly different.

About the AGS

Founded in 1934, the AGS focuses on protecting buyer interests from fraud and false advertising by retailers. In the interest of safeguarding consumers and creating a transparent buying process, over 3,400 diamond retailers, distributors, and professionals have joined the AGS today!

However, only 1 in 20 jewelers actually meets the criteria necessary to join the AGS. That’s because the organization insists on a rigorous application process and strict requirements for entry to ensure every member is providing a top-notch shopping experience to clients.

The AGS takes the same approach to diamond grading, and their labs are known to be uncompromising. They take pride in their work and promise superior ethical conduct and exacting grades for each diamond specimen!

How AGS diamond reports differ from GIA grades

So how do AGS and GIA diamond reports differ? Both groups provide comprehensive details about your diamond in an easy-to-read format, and they pride themselves on accurate grading. However, the scales and criteria they use to grade a diamond differ slightly.

When it comes to diamond cut, the GIA relies on a grading scale that ranges from Poor to Excellent, and there are 5 possible grades. In short, they focus on diamond proportions, polish, symmetry, weight ratio, and fire, brilliance, and scintillation in their grading.

In contrast, the AGS offers 11 possible cut grades! Diamond cut grades range from 0 to 10, which allows for more precise grading. While each number correlates to a “verbal” category—for instance, grades 5 to 7 rank as “Fair” on the AGS scale—11 possible scores mean more precise cut grades and the ability to create a hierarchy within each category.

The AGS actually uses this 0 to 10 grading scale for color and clarity as well, but the biggest differences can be seen in the grading of a diamond’s cut.

Furthermore, an AGS diamond cut grade requires extra testing for light performance in addition to studying the stone’s proportions and symmetry. Light performance tests require the use of ASET and Idealscope imagery as well as advanced analytical software to grade light play accurately.

Finally, the AGS actually has an entirely new category of diamond cut grade that the GIA does not. A grade 0, or Ideal diamond, is thought to be the cream of the crop, and these stones are completely optimized for light play and take up to 4x more effort to create!

What benefits does a GIA report bring to you?

So why should you want a GIA diamond report? Here’s a round-up of all the benefits you receive when buying a diamond with a GIA diamond grading report:📑

  • The GIA is the premiere diamond grading authority. They’re well-respected in the diamond industry, and a GIA diamond grading report can bring you peace of mind.
  • You get the satisfaction of knowing your diamond was painstakingly graded with strict requirements and transparency regarding any imperfections.
  • GIA diamond reports are thorough and easy to understand, so you can compare reports for multiple diamonds at once to ensure you’re getting the best stone for your money.
  • A diamond report means security against fake diamonds, as each gem must pass an inspection with the GIA DiamondCheck tool. So, you’ll never have to worry about someone selling you a forgery, as the GIA safeguards buyers against fake and undocumented lab-grown diamonds.
  • A GIA grade is great for your diamond’s resale value, as you have the paperwork to back up your gem’s quality!

Learn more about GIA's next-generation report—GIA Blockchain Diamond Grading Report📹👇🏻


Should you buy a diamond with a GIA report?

Both the GIA and AGS offer quality diamond reports and unparalleled grading processes to guarantee your diamond is graded fairly and transparently. However, despite this, the GIA is widely regarded as the authority on diamond grading due to their research regarding the 4Cs, and there’s a higher demand for their reports over AGS documentation.🙂

Overall, the GIA made the rules for diamond grading, and we highly recommend purchasing a diamond that has a GIA diamond grading report. A GIA report secures your diamond’s value, and having this paperwork is important when looking to insure your diamond or include it as part of an estate, will, etc.

But, if you’re more interested in your stone’s light performance, consider looking at diamonds with AGS reports to see if they would be right for you. The AGS is still an exemplary diamond authority, and while most prefer the GIA, the AGS is an excellent choice for individuals more interested in finding the sparkliest diamond possible!

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