What Is a GIA Certified Diamond (Complete Graded Process)

When shopping for a diamond, a term that will come up often is GIA diamond. The diamond you buy will have monetary and sentimental value, but you want to ensure that you get the best value for your money before you make the purchase.

It is important to understand every aspect of the diamond you are eyeing to make a smart decision, whether you are buying the diamond for yourself or a loved one. This guide will explain everything you need to know about what a GIA diamond is.

What is a GIA Diamond?

What is a GIA Diamond
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A GIA diamond has been graded by the Gemological Institute of America (GIA). Robert Shipley founded the GIA in 1931 for the study and research of gems. Today, the institute is the most trusted source of gem knowledge. Reputable jewelers, auction houses, museums, and individual collectors rely on the research and standards set by GIA to evaluate, grade, and verify gems.

GIA does not mine, sell or market gemstones. On the contrary, this research institution is responsible for assessing and grading precious stones to set universal standards that sellers and buyers can use to ensure they handle real natural gems. GIA standards streamline the study, sale, and purchase of precious stones, eliminating any confusion as to the value of a diamond.

A GIA diamond is tested, studied, and assessed under stringent conditions using powerful equipment and then graded according to the cut, clarity, carat, and color. After grading, the institute develops a unique report for that specific diamond. The comprehensive report contains all the information about a diamond, including a unique identifying number, 4Cs, and other elements such as fluorescence. You can use the report to verify that your diamond is GIA graded and natural.

Not all diamonds are GIA graded, but it is best to stick to those that are. This way, you are sure that you are investing in a real and not counterfeit diamond. GIA’s grading system is objective, unbiased, and based on verified scientific research.

The information on each diamond’s grading report allows you to compare diamonds based on the 4Cs to make an informed decision about the diamond that best suits you. Many insurance companies will ask for a grading report from GIA as part of the requirements for insuring your diamond.

How is A GIA Diamond Graded?

How is A GIA Diamond Graded
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After closely examining and studying a diamond, GIA gemologists compile a report containing information about the qualities of that particular stone. Each variety of diamond is unique—when every gemstone was formed underneath the Earth’s crust, it was exposed to different conditions. The stones were further exposed to blemish, scratches, and other forms of wear and tear that contribute to the stones’ uniqueness.

GIA’s gemologists use powerful microscopes to examine a stone’s characteristics such as color, cut, clarity, and carat weight, and more. When shopping for a diamond, be sure to ask for a GIA grading report, which will provide all the crucial details about the diamond you want to purchase. With this information, you can compare different diamonds and select one that best suits your needs.

So, what kind of information can you expect to glean from a GIA diamond report?

Report number

Each evaluated diamond is accorded a report number. This number can be found on the diamond’s girdle and helps to identify the diamond.


Common diamond shapes include square princess cut, oval, cushion, rose, marquise, pear, and brilliant round cut.


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The report will include the diamond’s width, length, and depth in millimeters.


This describes the diamond’s weight measured in carats.


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The GIA uses the alphabet to color grade diamonds. The grade starts with D to Z. Diamonds in the D-F scale are colorless and highly sought-after.

Those belonging to the G-J scale have a slight hint of yellow and are categorized as almost colorless. Diamonds on the K-Z scale have a more noticeable tinge of yellow and are considered colored diamonds.

Still, these should not be confused with fancy colored diamonds, which emit an array of spectacular colors and not just a hazy yellow.


Diamonds are further graded based on the blemishes or inclusions on the stone. In their natural habitat, gems are subjected to all kinds of elements, including heat, pressure, and general wear and tear.

A diamond with fewer flaws has more clarity and may fetch a high value. GIA gemologists also consider the type, size, number, and location of imperfections when grading a diamond’s clarity.

The clearest stones are graded as ‘flawless (F), followed by internally flawless (IF), very, very slightly included (VVS1, VVS2), Very Slightly Included (VS1, VS2), Slightly Included (SI1, SI2), Included (I1, I2, I3).


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A diamond is graded by how well it is cut at different angles. The different angles at which a diamond is cut have an impact on the way the stone reflects light, which then goes on to affect the diamond’s brilliance and sparkle.

A diamond can have an excellent cut or poor cut based on the GIA grade. An excellent cut will have outstanding brilliance, while diamonds with a poor cut will have less sparkle when exposed to light.


While clarity refers to a diamond’s absence of interior blemishes, polish refers to flaws on the surface of the diamond. When a diamond is cut, it is polished to achieve an outward shine.

But, during polishing, the diamond can be slightly damaged, resulting in tiny scratches and nicks. A gemologist will look for these small abrasions on the cutlet, table, or girdle when grading a diamond’s polish. The polish can be graded as excellent, very good, fair, or poor.


Symmetry refers to the diamond’s proportionality. Several aspects are considered when determining symmetry. These include height, pavilion depth, lower half-percentage variation,  and thickness of the girdle, crown angles, and more.

A diamond with excellent symmetry will have more brilliance and is considered to be more beautiful than one that is less symmetrical


Fluorescence is the glow a diamond emits under UV light. Fluorescence is usually blue, but the glow might be yellow, red, orange, or white in rare instances. According to GIA, not all diamonds have fluorescence; just 25 to 35% of diamonds will fluoresce.

Diamonds with strong fluorescence can have a hazy or milky appearance. Fluorescence is undesirable in large, high color and more expensive diamonds and can lower the price of the stone by as much as 10%.

But, for diamonds with a tint of yellow, fluorescence might improve the stone’s brilliance and its value too. Usually, faint fluorescence does not have a big impact on a diamond’s value, appearance, or desirability

Now you know how GIA grades diamonds. When shopping for a diamond,  not only should you ask for each diamond’s grading report; you should also compare loose diamonds using as many of the above criteria as possible. In the end, you will find just the right diamond for you.

What Is a GIA Certified Diamond

As you shop for your diamond, you might hear some jewelers mentioning or literature referring to the terms “GIA certified” or “GIA Cert diamond.” These are often used to refer to GIA-graded diamonds, but unfortunately, these terms are an inaccurate description of GIA’s mandate.

GIA is not a certifying body and insists that it never uses the term ‘certificate’ anywhere to describe its work or the subsequent reports it issues after studying and researching a diamond.

The institute uses standard criteria such as clarity, color, cut, and carat to grade a diamond; it doesn’t even place a value on diamonds and leaves it up to the jeweler to determine the monetary value of the stone.

After grading a diamond, GIA issues a grading report, which, as we have mentioned, contains all the information about the diamond’s characteristics. Sometimes, jewelers refer to this report as a certificate and market their diamonds using the terms’ GIA cert’ and ‘GIA certified.’


Do you need to buy a GIA diamond? Must you get your diamoned graded? The answer is yes and no. If you are in the market for a diamond, it is always best to take your time and check that any diamond you are eyeing has been verified to be natural and of good quality. This ensures that you get value for your money and is the biggest advantage of choosing GIA diamonds.

Contrary to popular belief, GIA diamonds are not any more expensive than other types of diamonds. Grading a diamond does not increase or decrease its price—the price of diamons is determined by other factors such as cut, color, and carat weight, among others.

Overall, a ring that has a GIA report is a much better and safer investment than one without any grading.

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