GIA Certified Diamonds

GIA Certified Diamonds

The GIA Certified Diamonds from the Gemological Institute of America, the World’s foremost authority in independent third-party diamond certification.

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What is GIA?

The GIA (Gemological Institute of America) is a non-profit organization that develops and implements standards for evaluating the quality of diamonds and is rightfully considered the most reputable gemological laboratory in the world.

GIA laboratories are located in key cities for the diamond industry: New York (USA), Carlsbad (USA), Johannesburg (South Africa), Gaborone (Botswana), Tokyo (Japan), Mumbai (India), Hong Kong (Hong Kong SAR, China), Ramatgan ( Israel), Bangkok (Thailand), soon an ultra-modern laboratory will open its doors in the diamond capital of the world – Antwerp (Belgium)

A GIA Diamond is a diamond certified by the Gemological Institute of America, the World’s foremost authority in independent third-party diamond certification. GIA diamonds are examined by a minimum of four highly trained diamond graders and gemologists. At each step of a diamond’s evaluation, a more senior staff member independently grades the stone.

The GIA’s mission is to increase consumers’ trust in diamonds and jewelry by upholding the highest standards of integrity, academics, science, and professionalism. They work toward this goal by providing jeweler and consumer education, conducting meticulous research, and developing state-of-the-art laboratory instruments for diamond inspections.

gia diamond

GIA Diamond Grading Standards

GIA diamonds are examined by a minimum of four highly trained diamond graders and gemologists. At each step of a diamond’s evaluation, a more senior staff member independently grades the stone. To ensure impartial evaluations, the distribution of diamonds to graders is a completely random process.

Still have questions? Contact a Diamond and Jewelry Expert at 214-527-4748 to start your diamond buying journey.

What does a GIA certificate look like?

There are several types of GIA certificates depending on the type and size of the diamond. In the photo below, we have collected the GIA certificates that the laboratory accompanies certified diamonds.

GIA Certified Diamonds
1. Gemstone Certificate – for Emeralds, Sapphires, Rubies, South Sea Pearls, Alexandrites.
2. Certificate of synthetic diamond.
3. Certificate of color diamond.
4. Natural diamond certificate (A4 format) – usually issued for diamonds weighing more than 0.90 carats
5. Natural diamond certificate (reduced format) – issued for diamonds weighing 0.30 carats or more

Certification of a diamond in the GIA laboratory can take several weeks, during which time experts gemologists will study the diamond and reliably determine its characteristics.

Typically, for diamonds weighing more than 0.50 carats, the GIA certificate looks like a sheet of thick A4 paper folded into 3 pieces. For smaller diamonds, the certificate may differ slightly from the illustration shown.

diamond grading report

The presence of a certificate for a diamond not only confirms the characteristics of the diamond, but also shows the Buyer the Seller’s willingness to conduct business openly.

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Information in the GIA certificate

Any diamond certificate issued by the GIA laboratory contains 3 information blocks. Let us examine the contents of a certificate for a 1.01 carat diamond that was sold to one of our regular Buyers.

diamond grading report
1. Block of general information about a diamond.
2. Block with geometric parameters of a diamond and a map of inclusions (only for A4 certificates).
3. Reference Information.
GIA Certified Diamonds

Block № 1

General information about the diamond

  1. GIA logotype
  2. Certification date
  3. Unique certificate number
  4. Cut shape
  5. Geometric dimensions (the first two digits are diameter, diameter measurements are made with a high-precision 3D scanner, the certificate indicates the minimum and maximum diameters according to measurement results, third digit – diamond height)
  6. Diamond weight, in carats
  7. Color Diamond 
  8. Diamond clarity
  9. Cut quality
  10. Polishing quality
  11. Symmetry
  12. Luminescence (glow in ultraviolet light)
  13. Laser engraving on girdle (side edge)
  14. Additional comments to the scheme of inclusions displayed in information block № 2


Background – a multiplied image of a diamond made by microprinting (one of the degrees of certificate protection)

GIA  Diamonds

Block № 2

Geometric parameters of the diamond

1. The number of the diamond certificate and a link to the GIA website, by clicking on which you can check the authenticity of the certificate.

2. A professional jeweler immediately pays attention to the proportions of a diamond.
They are important, for example, when choosing two diamonds for a pair of earrings. In this case, the diamonds should be as close as possible, in addition, it is important that the size of the area of ​​both stones does not differ by more than 2-3%, otherwise the diamonds will differ significantly from each other.

3. Map of inclusions.
Shows the type and nature of inclusions in a diamond, which are one of the protection degrees of a natural diamond. Volumetric coordinates of inclusions are unique for each stone and can be used to identify it.

GIA Certified Diamonds

Block № 3

Reference Information

1. Color scale adopted by the GIA.
The color is indicated by a letter from D to Z, in the upper part of the scale – colorless diamonds, the lower, the more noticeable the presence of a color shade.

2. Scale of diamond clarity.
In the upper part there are designations of diamonds with a minimum number of inclusions, in the lower part there are designations typical for diamonds with inclusions visible to the naked eye.

3. Scale of cut quality (excellent, very good, good, fair, poor).

4. GIA logo applied in a special way (one of the degrees of protection of the certificate).

5. QR-code of the certificate and a link to a website with a database of all issued GIA certificates


Depending on the type of gemstone, its size and unique characteristics, the content of information blocks may vary. For example, if a diamond has been exposed to external influences in order to change its color, then in 1 block of the certificate this will be indicated. For rare colorless and at the same time pure diamonds of type 2a, the GIA certificate is accompanied by a letter confirming the uniqueness of the stone.

The GIA certificate guarantees you the characteristics of a diamond and gives you the opportunity to adequately assess the value of a jewelry!

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Authenticity of the GIA certificate

It is important to make sure not only the authenticity of the diamond, but also the authenticity of the diamond certificate. In addition, it is important to know whether the certificate corresponds to the diamond that is fixed in your jewelry.

The certificate has several degrees of protection, such as microprinting, watermarks, holographic images. You can check the compliance of the certificate by entering its number on the official website of the GIA.

On the side face (girdle) of almost all diamonds certified in the GIA laboratories, the GIA logo and the certificate number are applied with a laser. The number engraved on the diamond can be seen with a 10x loupe.

diamond grading report

GIA Diamond Grading Report

The GIA Diamond Grading Report is issued for diamonds that fall in the D-Z color range. This detailed report includes a full quality analysis of shape and cutting style, measurements, carat weight, color grade, clarity grade, cut grade (for brilliant round-cut diamonds), polish and symmetry assessments, and fluorescence.

The report also includes a plotted diagram indicating the relative size and location of clarity characteristics, a proportion diagram, and GIA grading scales.

GIA Diamond Dossier Report

GIA Diamond Dossier Report

The GIA Diamond Dossier® is issued for diamonds between 0.15 and 1.99 carats that fall in the D-Z color range.

This report includes all of the information featured in the Diamond Grading Report without a plotted diagram. All diamonds accompanied by a Diamond Dossier are laser inscribed and registered in the GIA inscription registry.

Brief History of GIA

Brief History of GIA

Gemstone manufacturers from around the globe send diamonds and gems to the GIA for expert examination and analysis.

Founded in 1931, the Gemological Institute of America (GIA) is an independent, non-profit organization widely considered as the world’s foremost authority in gemology. Introduced in 1953, their diamond and gemstone grading system is recognized as an accepted standard worldwide.

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Diamond Shape

Diamond Shape

Although the brilliant round-shaped diamond has long been the most popular, many consumers prefer alternative forms, including cushions, ovals and pears, among other things. At USA Diamonds, we offer the most popular diamond forms in our search for diamonds:

Diamond Color

Diamond Color

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Diamond Clarity

Diamond Clarity

How pure is the diamond? Diamond clarity is a rating on the Perfect to Inclusive scale, which measures the amount and location of impurities in a diamond. Inclusion is an internal or external characteristic or defect that occurs during the natural formation of the terrestrial diamond. Most diamonds contain impurities

Diamond Cut

Diamond Cut

Diamond cut is the summary of a diamond’s proportions evaluated using the attributes of brilliance, fire, and sparkle. While high marks of color or clarity affect a diamond, it’s the cut that defines its proportions and ability to reflect light. This article is about diamond cut. Click here to learn about the different Diamond Shapes. The diamond cut scale is

Diamond Fluorescence

Diamond Fluorescence

When UV light hits a diamond with fluorescent properties, the stone emits light. Most often blue, it can also be shades of green, yellow, white or red. Fluorescence can occur at different intensities. Gemological laboratories such as the GIA rate diamonds for fluorescence on a scale from “None” to “Very


There are four C’s that are used to describe a diamond: cut, color, clarity, and of course, carat. The carat is the standard unit of measurement used to indicate the weight of diamonds and precious gemstones. Since 1913, carat weight has been gauged against the metric system, with one carat equaling 0.2 grams or 0.007 ounces. Carat weight

FAQ for GIA Certified Diamonds

What makes a diamond GIA certified?

The GIA tests diamonds and grades them based on the 4 C’s: carat weight, cut, color, and clarity. Testing is conducted under stringent guidelines not to miss any flaws. The institute then files a test report and signs off on the diamond’s quality. The diamond is then considered “GIA certified.”

Does GIA certification matter?

Yes, GIA IS important because GIA is the leader in the grading industry. They devised the 4C’s! They wrote the book that everyone uses to Grade, Buy, Sell, Price, and Compare Diamonds by. Their Certifications (which are really called Diamond Reports), are the most accurate reports you can get in the WORLD!

Do GIA certified diamonds cost more?

Having a diamond graded by GIA is not expensive. GIA charges as little as $48 for a grading report for a diamond weighing 0.70 ct to 0.99 ct, and as little as $80 for a diamond weighing 1.00 ct to 1.49 ct. (Most jewelers factor grading fees into the price of the diamond.)

Which is better GIA or AGS?

The only difference between AGS and GIA is the parameters for measuring Cut quality. With AGS, the cut grading scale is from 0-10 (along with descriptive wording), 0 means Ideal and 8-10 means Poor. The GIA scale includes Excellent, Very Good, Good, Fair and Poor.

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