All About A GIA Diamond Grading Report

GIA Diamond Grading Report
Worthy Staff

By Worthy Staff | Mar 26th, 2020

So you’ve decided to sell a diamond. You may know how much you bought it for, and be aware that, much like a car, the resale value isn’t going to be as close to the amount you paid for it as you’d like it to be. You might even have a report from your jeweler or a grading lab that details the quality of your stone, but how can you figure out how much it’s really worth? And if you’re not sure what it’s worth how do you know a buyer isn’t taking advantage of you? This is exactly why we created Worthy: we saw a need for a service that allows consumers to reach the wholesale buyers that specialize in pre-owned jewelry with a team of diamond experts (that’s us!) advocating for them and their stone. One way that we insure you are getting the best possible deal is by providing a complimentary grading from GIA.

What Is A Diamond Grading Report?

A diamond grading report documents the specific characteristics of a diamond. It is important to recognize that many stores will issue their own documentation and diamond reports that are graded by in-store gemologists, some of whom may have been educated and trained by GIA – the Gemological Institute of America. For example, Tiffany & Co issues their own exclusive grading report, as does Zales. However, only GIA can issue a GIA grading report.

GIA does not sell diamonds or gemstones

What Is The GIA?

GIA, a nonprofit organization, is a public benefit research and educational institution and acts as an independent and impartial entity for evaluating the quality of diamonds and gems and delivering unbiased information. GIA does not sell diamonds or gemstones, nor does it represent the interests of any retailers or sellers.

What Is A GIA Diamond Grading Report?

The grading reports issued by GIA (Gemological Institute of America), are recognized as the most respected and impartial reporting in the diamond industry. With objectivity and expertise as its hallmarks, GIA ensures the integrity and accuracy of every grading report it issues. A report from GIA is an expert, un-biased statement of a diamond’s identity and quality characteristics.

A GIA report isn’t an appraisal of financial value; rather it is an assurance of the diamond’s quality, with clear disclosure if the material is natural, synthetic or treated to enhance or alter its appearance. The report provides the kind of evidence that is vital for understanding and evaluating a diamond so as to be able to make a confident diamond sale.

GIA tests every diamond submitted to determine whether it is natural, a synthetic or simulant, and discloses any treatments discovered during the examination. 

Having a GIA diamond grading report accompanying your stone is a comprehensive, methodical and scientific evaluation of the qualities that contribute to a diamond’s overall value. These credentials enable people on both sides of any transaction to operate with confidence, knowing GIA has issued the grading report on a diamond.

Worthy recognizes the importance of impartial reporting and objectivity in evaluating precious stones and offers a complimentary GIA diamond grading report to each customer.

Why Worthy Uses GIA Grading Reports

Standards: GIA has established the worldwide standards for diamonds. GIA developed and maintains the methods and best practices for evaluating diamonds worldwide. As creator of the 4Cs of diamond quality and the GIA International Diamond Grading System™, GIA established the common language for describing the quality of D-to-Z color diamonds.

Accuracy and Consistency: Every GIA laboratory operates under the same set of standard procedures and principles designed to ensure the objectivity and accuracy of every gem identification or grading report issued. These tenets are supported by research, highly trained staff, robust quality control systems, and a suite of best-practices.

Protect: Through research, education, and unbiased gem grading and analysis, GIA strives to protect the gem and the jewelry buying and selling public by setting, adhering and maintaining the diamond global quality standards.

How To Read A GIA Diamond Grading Report 

A GIA Diamond Grading Report is an assessment of the 4Cs of your diamond – all the technical details you would want to know about your stone. the GIA provides different kinds of reports. These are full Diamond Grading Reports, Diamond Dossiers, and eReports, which are online only.

How To Read A GIA Diamond Grading Report

Report Number

If you look at the left-hand of your full GIA diamond report, you’ll see the report number – a unique number pegged to your diamond. If you go to, you can click “report check” on the top menu bar and type in your report number – this will pull up all the information in your report.

Cutting Style and Measurements

Below your report number, you’ll find the shape and cutting style, followed by the measurements of your stone. The shape and cutting style tells you the shape of your diamond and the style of the cut. For example, a “rectangular step cut” is an emerald cut diamond; and a “square modified brilliant” is more frequently known as a princess cut diamond.

Then you have the measurements of your stone – the physical dimensions of the stone measured to the nearest hundredth of a millimeter.

The GIA 4Cs Of Diamond Quality

Diamond Clarity

Color: The color of a diamond is the first of the 4Cs. On your GIA Diamond Grading Report, you will see color directly under the grading results header, rated on a scale from D-to-Z. The scale is alphabetical and rates the absence of color. A diamond rated a D for color means that it is colorless – a desirable property. On the other end of the spectrum, Z means that a diamond is yellow or brown-tinged, which reduces its value considerably. The descriptors used alongside the diamond’s individual letter grade are colorless, near colorless, faint, very light, and light. Another important note to mention is that if the letter has an asterisk next to it, the stone might have been treated specifically to enhance its natural color. There is also a GIA Colored Diamond Grading Report that will specify the fancy color of a diamond and if treatments were detected.

GIA Color Scale
GIA Color Scale

Carat Weight: The second of the 4Cs, carat weight, is often thought of as the most closely related to a diamond’s price. This is logical, because the heavier a diamond is the larger it is, and large diamonds are quite rare. You will notice on your report that the stone was weighed to the closest hundredth of a carat.

Clarity: Clarity is harder to determine than a diamond’s color or weight, and requires a detailed analysis of the stone using professionally trained staff. The main purpose of examining a diamond’s clarity is to find all its inclusions residing in its interior or blemishes on its surface. Clearly, the less inclusions there are, the more expensive the stone. On a GIA Diamond Grading Report or Colored Diamond Grading Report, the clarity characteristics are drawn on a plotting diagram. For a GIA Diamond Dossier report the clarity characteristics are listed. Both reports list the clarity characteristics in order of severity that they appear in the diamond. Severity is determined by the number, size, characteristics, and position of these inclusions. Overall, the stone will be rated for clarity as Flawless, Internally flawless, VVS1 or VVS2 (Very Very Slightly Included), VS1 or VS2 (Very Slightly Included), SI1 or SI2 (Slightly Included), or I1, I2 or I3 (Included).

GIA Clarity Scale
GIA Clarity Scale

Cut: One of the only properties of a diamond that is attributed to human’s efforts at shaping it, and enhancing its beauty, cut is an important part of the 4Cs. To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. The scale ranges from Excellent to Poor (with Very Good, Good, and Fair in between) and is based on a range of factors like polish, symmetry, weight, durability, and scintillation. This is one of the measurements that is accompanied by a diagram that shows the diamond’s profile and other perspectives.

Completing The Picture: GIA’s Other Measurements

In addition to the 4Cs, there are other characteristics identified in the report that tell a person more about the diamond that they’re viewing. Fluorescence is one of the other distinguishing characteristics that is determined by the diamond’s ability to emit a glow of a certain color when exposed to UV light. A very small percentage of diamonds exhibit fluorescence. The fluorescence scale begins at none, and runs through faint, medium, strong, and finally, very strong.

Additional grading information found on the report includes the polish and symmetry of the stone. Polish evaluates the smoothness of a diamond’s surface and symmetry is the evaluation of the alignment of the stone’s facets, outline, placement and shape. Polish and symmetry are graded using the range Excellent to Poor.

A diamond plot is a unique diagram of your stone (think of it like a fingerprint) mapping out all the clarity characteristics of the diamond. Blemishes, which are external, are marked in green on the plot, while inclusions – internal imperfections in the diamond, such as crystals (mineral formations) – are marked in red.

The proportions diagram shows all the technical measurements for the cut of the stone. This is useful for people who wish to analyze the diamond based on numbers like table percentage, depth percentage, crown angles, pavilion angles and girdle thickness.

The proportions diagram
The proportions diagram

There is also a comments section in the report, which notes specifics about other characteristics that may have been observed during grading. Comments can cover such features as a unique blemish, and may include more details on how a diamond may have been treated to improve clarity , or other relevant pieces of information.

Additionally, inscribing a diamond is a modern, effective way for one to identify it without accompanying paperwork. With a microscope, one can usually manage to find where the stone was laser-inscribed with its identifying information.

GIA Report
GIA Report

Benefits of A GIA Grading Report

A GIA grading report is an unbiased analysis using established global diamond standards with the ultimate goal to protect the public, the buyer and the seller, be it the newly engaged, the divorcee, as well as the jewelry stores and buyers.

There are additional elements contained within the report that further this notion. The system that GIA uses to store diamond measurements and identities is vast, and each stone is denoted by a specific GIA report number. This number is displayed at the top of the report, and is used to reference your stone’s online listing. Diamond sellers can use this to show prospective buyers that their desired stone has been closely scrutinized by professionals and characteristics are stated accurately.

Benefits of A GIA Grading Report

The report also has a QR code at the bottom, which can be scanned by a smartphone, and sends the viewer online to GIA Report Check, which displays the report information for the gem in question. These measurements more often make a GIA report a non-negotiable addition to any trade or sale. GIA’s efforts at achieving meticulous accuracy for every stone they inspect help make the industry safer as a whole by preventing fraud. Anyone with any amount of experience can rely on a GIA report to speak for itself in any negotiation, but comprehension of the report’s finer details is recommended.


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