Diamond Certification Guide

Gemology laboratories such as the Gemological Institute of America (GIA) have created a certificate of quality that can be issued for any diamond whose dimensions, carat weight, symmetry, color, and clarity meet the required standard.


diamond certification

Trained professionals evaluate, scrutinize, and measure the diamonds using professional tools such as a microscope and a diamond grading chart. Several lab entities exist and it’s important to know which ones are trustworthy and reliable, and which ones are not. Because diamond certificates are not created equal, the price and value of diamonds are not always comparable across varying certifications. Ensure that you buy a diamond with a certificate from a highly reputable grading entity and that you review the diamond and diamond certificate closely before purchase.

While diamond certification shares similarities with diamond appraisal they are still two different things. A certificate or stone grading will assess the diamond and provide a “blueprint” of the diamond including all the individual characteristics of the stone. An appraisal, on the other hand, is a report on the diamond’s monetary worth based on diamond quality and current market conditions.

At ICONIC we believe in trust built on complete transparency and that is why we offer our clients the opportunity to buy a diamond and gems that have been carefully examined and graded by professionals.


A diamond certificate, also known as a diamond grading report, is a report created by a professional gemology laboratory. A professional gemologist will measure, examine, and assess the qualities of each diamond in order to produce an unbiased report within their diamond labs.

diamond certification

Some of the world’s most respected independent grading labs include the Gemological Institute of America (GIA) and the American Gem Society (AGS). Grading standards vary between labs, making it important to choose a lab known for its rigorous standards and strict protocols. Each entity grades and describes diamonds differently and sometimes the difference is significant.

Diamond certificates give buyers confidence that what they are buying a diamond as the diamond’s quality is accurately and transparently described. For those that need to know the diamond’s current monetary value though, an appraisal is needed. Appraisals are usually carried out for insurance purposes.


A diamond certificate will include details of the diamond’s dimensions, carat weight, color, and more. You may see the diamond grading chart for more details on the 4cs. Essentially certification or grading gemologists and experts will look at a diamond color, clarity, cut, carat, length, width, and more. All of these characteristics, as well as existing standards and special tools, help certification labs to assess the diamond’s quality.

However, different grading entities may describe diamonds differently. Sometimes these differences are subtle and sometimes they are substantial. It’s important to know which gemological lab is trustworthy and reliable.


While certified diamonds aren’t necessarily inherently better than non-certified diamonds, they still provide buyers with a level of security because buyers know that each diamond purchase is a diamond that has undergone careful scrutiny and is certified high quality.

Certified diamonds have grades based on their 4cs and physical qualities and those who buy a diamond with a certificate are assured they are getting what they pay for and know the full quality of the stone. When buying diamonds for engagement rings or other jewelry, it is still recommended to buy one with a certificate.

However, it’s also important to note that diamond certification is a guide of a diamond’s worth but buyers still need to consider and evaluate the price of the diamond before making the purchase. While it’s understandable that buyers would want highly-graded diamonds for engagement rings they should also be able to see that the price reflects the beauty indicated on the certificate both in the paperwork and to their own naked eye.


Types of diamond certification in the diamond industry:



GIA stands for Gemological Institute of America, and they are a gem lab responsible for grading diamonds. GIA has robust procedures in place to ensure a diamond’s anonymity and the objectivity of the whole grading process. GIA doesn’t certify diamonds per se, but rather it grades them. A GIA diamond grade report is an unbiased assessment of diamond quality characteristics. The terms “GIA certified” and “GIA diamond cert” are commonly used in the jewelry industry to refer to diamonds that have undergone GIA’s rigorous grading process and to the reports that accompany them.


American Gem Society (AGS ) established the first diamond grading standards guidelines in 1966 and these standards still influence the jewelry industry today. They produce unbiased diamond grading reports through their laboratories, grading both mounted and unmounted gems. They can only assign a diamond cut grade for loose diamonds that are Round Brilliants, square Princess cuts, Emerald cuts, Oval cuts, and Cushion cuts.

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, AGS takes 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).


The European Gemological Laboratory is another gem grading organization made up of independent gemological laboratories that were established in 1974. They issue European Gemological Laboratory diamond certifications and for the most part, EGL certified diamond will compare equally in quality to a GIA certified diamond that is graded two color grades and one clarity grade lower.


International Gemological Institute (IGI) is an institute that grades diamonds institute who performs similar functions to the GIA, in that they both issue diamond grade reports and diamond certifications. IGI operates 18 laboratories across the globe performing IGI diamond certification on earth grown and lab-grown diamonds.


Independent Gemmological Laboratory (IGL) issues diamond certifications and are not affiliated with any diamond manufacturers. To maintain the quality of their work, IGL uses a strict vetting process ensures that we only produce IGL Diamond Certificates for stones that are natural and high-quality diamonds and that those that don’t pass a certain standard will be rejected.


Hoge Raad Voor Diamant HRD Antwerp is Europe’s leading authority when it comes to diamond grading applying advanced techniques in their state-of-the-art laboratories and each HRD diamond grading report comes with security features to protect against counterfeit certificates.


Gemological Science International (GSI) diamond certification includes GSI diamond grading reports and colored stone grading reports.


Gem Studies Laboratory is an Australian-based organization offering diamond grading and gem testing. GSL provides diamond certification and gem authentication reports to established world standards.

Frequently Asked Questions

There are a lot of factors to take into account which will determine the value of a 1-carat diamond, including the cut, clarity, color, and shape of the stone. Prices currently vary from anything from $1,800 to in excess of $12,000.
To get a diamond certified by the GIA, it must be sent to an official GIA gemological laboratory. They will perform an analysis of the stone, grade it, and issue a certificate. This certificate is referred to as a “diamond grading report”. Your local fine jewelry retailer is qualified to obtain a GIA report and to explain its contents to you.
Flawless or FL is the highest grade for clarity. An FL diamond has no imperfections. For color, D or completely colorless diamond is the highest grade quality.
Lab-grown diamonds are real, ethically sourced, and conflict-free, as well as being eco-friendly. They are also more affordable.
Most diamond certifications can be checked online at the relevant grading institute websites. for a convenient means of verifying your diamond grading report. GIA is the preferred diamond quality grading organization in the United States.
International Gemological Institute (IGI) is a gem grading institute that performs similar functions to the Gemological Institute of America (GIA), in that they both issue diamond grading reports and diamond certifications. GIA diamond reports are held in higher regard within the American market but both organizations have a good reputation within the jewelry industry.
You can be assured that GIA-certified diamonds are accurately assessed and graded giving you verification of the quality you thought you purchased and whether it is in fact what you purchased.
Diamonds are graded on a scale to measure cut, clarity, color, and carat weight to determine their value. For example, as an industry standard, the GIA uses a color-grading scale from D-to-Z, with D being the highest grade.
To get a diamond certified by the GIA, it must be sent to one of their official testing laboratories. They will perform an analysis of the stone, grade it, and issue a certificate known as a “diamond grade report”.