AGS Laboratories FAQs
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AGS Laboratories FAQs

Frequently Asked Questions

1. What does AGS Laboratories do?

The AGS Laboratories offers diamond-grading services to members of the jewelry industry only. Our diamond grading reports provide an expert opinion from an unbiased, independent third-party diamond laboratory for the consumer. We grade both mounted and unmounted diamonds.

Any diamond shape can receive a diamond grading report, but we can only assign a diamond cut grade for loose diamonds that are Round Brilliants, square Princess cuts, Emerald cuts, Oval cuts, and Cushion cuts. We do not grade fancy color diamonds.

2. How can I verify an AGS Laboratories diamond grading report?

You can visit our AGS Laboratories Report Verification page. This enables you to check that the information on your diamond grading report matches the information stored in the AGS Laboratories report database. To check the diamond grading report, please enter your AGS report number and the carat weight from your diamond grading report.

3. How can I get a diamond graded by the AGS Laboratories?

If your business is in the jewelry trade, we’ll be happy to set up an account. Please see Become a Client or call Client Service. If you’re not in the jewelry trade, please visit an American Gem Society retail jeweler in your area. An AGS retail jeweler may be able to submit the diamond to the AGS Laboratories for you. 

4. Can the AGS Laboratories laser inscribe my diamond?

If your business is in the jewelry trade, we’ll be happy to set up an account and inscribe your diamond. Please see Become a Client or call Client Service. If you’re not in the jewelry trade, please visit an American Gem Society retail jeweler in your area. An AGS retail jeweler may be able to submit the diamond to the AGS Laboratories for you.

5. How can I replace a lost AGS grading report?

If your business is in the jewelry trade, we’ll be happy to set up an account and provide a replacement document. Please contact usIf you’re a consumer, you can request a replacement document directly from the Laboratory.  Please contact us and provide the AGS number for the document you’ve lost. 

6. How can I find an American Gem Society jeweler in my area?


7. How can I get an appraisal on my diamond ring?


8. If I’m sending diamonds to the AGS Laboratories for grading, what are the shipping requirements?

A company memo or invoice must accompany each shipment. Inbound shipments can be made using your choice of carrier.

If shipping loose diamonds, each stone should be listed on the memo, along with the carat weight and U.S. dollar value. Each diamond submitted must be in an individual diamond parcel paper, and the paper must indicate the weight.

If shipping mounted goods, please clean them before shipping. Be sure to list each item on the memo, along with the carat weight and U.S. dollar value. Each item submitted must be in an individual parcel paper or plastic bag, and the paper or bag must indicate the weight.

9. What kind of gemstones does the AGS Laboratories Grade?

We grade both loose and mounted diamonds. The AGS Laboratories is a trade-only diamond laboratory and only accepts diamonds from jewelers and manufacturers. If you would like to have your diamond receive an AGS Laboratories diamond grading report, we recommend you find an American Gem Society jeweler in your area.

10. Can any jeweler sell a diamond with an AGS Laboratories diamond grading report, or does it have to be a jeweler who is an AGS member?

Any jewelry store can sell AGS Laboratories diamond grading reports; however, only an American Gem Society member can sell the Diamond Quality® Certificate

11. Does the AGS Laboratories disclose if a diamond has been treated?

The AGS Laboratories screens every diamond for potential treatments like High Pressure High Temperature (HPHT), fracture filling, and laser drilling. The AGS Laboratories will grade an HPHT-treated diamond if the fact of its treatment is disclosed upon receipt. The AGS Laboratories does not grade fracture-filled diamonds. However, the AGS Laboratories does grade diamonds that have been laser drilled. All treatments are disclosed in the "Comments" section of an AGS Laboratories diamond grading report.

12. How should I clean my diamond?

You should take your diamond to be cleaned and inspected by a professional jeweler at least once a year. If you are cleaning your diamond at home, you can purchase cleaning agents at your jeweler. You may also use a solution of warm water and a mild liquid soap. Apply the solution to the diamond gently, using a cotton swab or soft bristle toothbrush; rinse thoroughly and dry with a soft cloth.

Cut Grade

1. What is Cut?

The jewelry industry refers to Cut in two ways:
  •  As a reference to the shape, style, and faceting of a diamond.
  •  How well a diamond is fashioned (e.g., brilliance, fire, and scintillation).

2. What is an Ideal Cut diamond?

There is much debate in the diamond industry about what constitutes an actual Ideal Cut. An AGS Ideal Cut is a diamond where all the diamond’s Cut quality factors (light performance, proportions, and polish and symmetry) exist at the highest possible levels, making the maximum contribution to the diamond’s beauty and value.

3. What are the factors that determine a diamond’s Cut Grade?

The AGS Laboratories uses the AGS Performance-Based Cut Grade system, which is based on the overall performance of a diamond, specifically in the area of Light Performance. When analyzing the overall performance of the diamond, we take the following into consideration: light performance (contrast, leakage, dispersion, and brightness), proportion factors (girdle thickness, Culet size, Weight Ratio, durability, and tilt), and finish (Polish and Symmetry).

4. Is there a Cut Grade for fancy shape diamonds?

Yes. In 2006, the American Gem Society released its fancy shape Cut Grade research, which concluded five years of research by a team of diamond experts, optical physicists, and mathematicians. The AGS Laboratories' Diamond Quality® Document was the first diamond grading report ever to issue a fancy shape diamond cut grade. Currently, the AGS Laboratories is grading the Princess cut, Emerald Cut, Oval cut, and Cushion cut shapes. Other fancy shapes will follow.

5. What is Brightness?

Brightness is the amount of white light in a diamond that is returned to the observer.

6. What is Brilliance?

Brilliance factors in both a diamond’s brightness and contrast. When a diamond gives off a large amount of light through the table, it is considered brilliant. When some facets are darker than others in intense lighting (think sunlight), the diamond will appear brighter.

7. What is Contrast?

Contrast is the effect created by the light and dark patterns seen when observing a faceted diamond. This can be positive or negative in its optical effect. Usually it is caused by, but not limited to, the observer's head.

8. What is Dispersion?

Dispersion is the separation of white light into colors by the refraction in a diamond.

9. What is Durability?

Durability is a diamond’s resistance to chipping or breaking.

10. What is Leakage?

Leakage is defined as the areas in a diamond that do not return light.

11. What is Weight Ratio?

Weight Ratio is the millimeter footprint of a diamond versus its weight.

12. What is Tilt?

Tilt is the point at which the girdle reflects in the table of a diamond. It is defined by the minimum pavilion angle allowed for each table size.

13. What is Luster?

Luster is the quality and quantity of light reflected from a gem's surface.

14. What is Polish?

Polish is the quality of the diamond's surface and edges.

15. What are Proportions?

Proportions are the size and angular relationships among the main parts of the diamond. AGS Laboratories diamond graders consider the following factors when evaluating Proportions: Table Size, Crown Angle, Girdle Thickness, Pavilion Angle, Culet Size.

16. What is a Culet?

The Culet is the point on the bottom of a diamond's pavilion. A diamond's Culet may be pointed or it may be blunted with a small facet.

17. What is Shape?

Shape is the outline of the diamond
like marquise, pear, or oval.

18. What is Symmetry?

Symmetry is the exactness of the balance and evenness of the diamond's shape and facets.

19. What is Scintillation?

Commonly referred to as “sparkle,” Scintillation is the effect that occurs when the diamond, the observer, or the illumination conditions are in movement. When movement occurs, flashes of both white and colored sparkles can be seen. The white sparkles are defined as Flash Scintillation and the colored sparkles as Fire Scintillation.

20. What is Flash Scintillation?

Flash Scintillation is the dynamic pattern of white sparkles observed when the diamond, observer, or illumination sources are in movement.

21. What is Fire Scintillation?

Fire Scintillation is the dynamic pattern of colored sparkles observed when the diamond, observer, or illumination sources are in movement.

22. What is a Scintillation Map?

A Scintillation Map is a color-coded diagram illustrating a diamonds potential to exhibit flash and or fire scintillation across the broadest range of lighting conditions.

23. What is a Flash Scintillation Map?

A Flash Scintillation Map map is a computer generated map showing the areas of the diamond that have the highest probability to exhibit flash scintillation across the broadest range of lighting conditions.

24. What is a Fire Scintillation Map?

A Fire Scintillation Map is a computer generated map showing the areas of the diamond that have the highest probability to exhibit fire scintillation across the broadest range of lighting conditions.

25. What is a Scintillation Patterning Map?

A Scintillation Patterning Map is a color coded map showing the areas of the diamond that are most likely to exhibit small, medium, and large virtual facets (sparkles).

1. What is Carat Weight?

Carat Weight is a diamond's physical weight measured in metric carats. One metric carat equals 0.200 grams, or one-fifth of a gram. In more familiar terms, that is a little more than 0.007 of an ounce avoirdupois. (Avoirdupois is the common weight system we use in the United States.) For precision, the carat is further divided into hundredths, and each of those is called a point. In the AGS Laboratories diamond lab, Carat Weight is measured using a digital scale.

2. How does the AGS Laboratories determine the Clarity Grade of a diamond?

Clarity is the degree to which a diamond is free from inclusions and blemishes. Inclusions are internal characteristics; blemishes are external characteristics. Many diamonds have Clarity characteristics that can be seen only with magnification. The Clarity grade is subjectively based on the nature, location, size, quantity, and relief of the inclusions. At the AGS Laboratories, a minimum of two experienced diamond graders grade each diamond for the Clarity grade.

3. How does the AGS Laboratories determine the Color Grade of a diamond?

Color normally refers to where a diamond's Color falls within the range from colorless to light yellow or light brown. At the AGS Laboratories, the Color of a diamond is determined by at least two experienced color diamond graders using a set of master diamonds.

4. Does the AGS Laboratories place a value on the documents it issues?

No. The AGS Laboratories provides an unbiased, independent, and expert third-party opinion on the 4Cs of a diamond. You never should see an appraisal amount on a diamond grading report. Price should be determined by the jeweler, not the laboratory.

5. What is the experience level of the AGS Laboratories diamond graders?

Each diamond grader is required to pass the Gemological Institute of America (GIA) Diamond and Diamond Grading courses. In the AGS Laboratories, several Certified Gemologists oversee the work of each diamond grader.

6. How many diamond graders examine each diamond to determine Cut, Color, and Clarity?

A minimum of two (2) diamond graders analyzes each diamond factor.

7. Does the AGS Laboratories grade colored diamonds?

The AGS Laboratories does not grade colored diamonds.


1. What is laser inscription?

Using a microlaser beam, the AGS Laboratories can inscribe the assigned AGS number, brand logos, and messages on the girdle of a diamond.  Laser inscription does not damage the diamond nor does it affect the Color or Clarity of a diamond.  The laser inscription can be viewed with a jeweler’s loupe. 

2. What is a Diamond Quality® Document (DQD)?

The AGS Diamond Quality® Document (DQD) is the world's leading diamond report for Cut, and the first one offering a performance-based cut grade for the Round Brilliant as well as for fancy cuts, including Princess, Oval, Emerald and Cushion-shape diamonds. The DQD also provides a complete grading analysis of Color, Clarity, and Carat Weight.  We examine the performance of a diamondhow it handles and refracts light. With the DQD, diamonds can receive a Cut Grade up to AGS Ideal.

The AGS DQD also is available in the Platinum DQD format.  This format provides the same detail as the DQD; it also includes a light performance map based on patented AGS ASET® technology.

3. What is a Diamond Quality® Report (DQR)?

The AGS Diamond Quality® Report offers a complete grading analysis of a diamond, including the profile with measurements, and a custom plot. The Diamond Quality® Report provides an option for diamonds that have less-than-Ideal grades on Cut, Polish, or Symmetry and, therefore, shows a maximum grade of AGS 1 (Excellent).

The Diamond Quality® Report (DQR) is available in a number of formats, can be printed for any shape diamond, and is available with or without the AGS performance-based cut grade. The maximum grade available on the DQR is AGS 1 (Excellent). 

The AGS Laboratories proportion-based Gold Diamond Quality
® Report (DQR) is based upon the patented AGS light performance system and provides a proportion-based Cut Grade for the standard Round Brilliant stone. This report can be printed for any shape diamond. The Gold DQR report offers a complete grading analysis of the 4Cs: Cut (standard Round Brilliant), Color, Clarity, and Carat Weight, and features word descriptors ranging from Ideal to Very Poor, so that it gives a clear, concise explanation of the diamond's quality.
See More Details

4. What is a Diamond Quality® Analysis (DQA)?

The Diamond Quality® Analysis (DQA) is a pocket-size document for stones weighing up to 1.99 carats. The DQA offers a complete grading analysis, without a plot, and includes one required laser inscription for diamond identification. This is the perfect document when you need all the details for diamonds weighing less than two carats in an easy-to-travel format. With the DQA, diamonds can receive a Cut Grade up to AGS Ideal.

5. What is a Diamond Quality® Certificate (DQC)?

The AGS Diamond Quality® Certificate (DQC) is a diamond grading report available exclusively for American Gem Society retail jewelers. This is the first and only certificate to guarantee authenticity and provide accountability for the diamond’s grade. 

The DQC provides a complete diamond grading analysis of the 4Cs: the diamond’s Cut Grade, Color Grade, Clarity Grade, and Carat Weight, as well as the light performance map  (AGS ASET® image) and any laser inscriptions on the girdle of the diamond. The DQC comes in a high-quality presentation folder and is not laminated, so the AGS titleholder may sign the certificate, ensuring this diamond is certified and of the highest quality.

6. What is a Diamond Consultation™ (DC)?

The AGS Diamond Consultation™ (DC) is a product for diamonds weighing 4.99 carats or less and provides Shape, Weight, Clarity, and Color information about the diamond, as well as a plot of the diamond inclusions and/or blemishes.  The DC provides, in a compact credit-card size fold-over document, a concise snapshot of a diamond with an easy-to-read spine for quick filing and identification.

7. What is a Scintillation Report?

The AGS Laboratories Scintillation Report is a limited-production addendum report available exclusively for the RITANI Reserve program. The information provided in the report supplements the grading information provided in an accompanying grading report and certifies that the physical specifications and assigned quality grades are accurate within recognized gemological tolerances. The supplementary information provided in the Scintillation Report includes a Flash Scintillation Map, a Fire Scintillation Map, a Scintillation Patterning Map, and a photomicrograph of the diamond.
Have a question that's not listed here? Contact us at AGS Laboratories.

Mission Statement

The American Gem Society (AGS) is a nonprofit trade association of fine jewelry professionals dedicated to setting, maintaining and promoting the highest standards of ethical conduct and professional behavior through education, accreditation, recertification of its membership, gemological standards, and gemological research.

The Society is committed to providing educational products to inform and protect the consumer and to contributing to the betterment of the trade by creating industry standards to protect the jewelry-buying public and the fine jewelry industry as a whole.

AGS Laboratories, founded to support the AGS mission, is a nonprofit diamond grading laboratory with a mission of consumer protection. Adhering to the AGS Diamond Grading Standards, AGS Laboratories is dedicated to offering diamond grading reports that provide consistency and accuracy based on science.

American Gem Society