Diamond Certification: The key to customer satisfaction and value addition

By Engineer Clever Sithole

Buying a polished diamond is like buying a car. It is not enough to simply glance at it and call it a day; you want to try it on for size and be sure all the corresponding certifications and paperwork are available to back up your purchase. For many couples searching for the perfect gemstone, one term will come up a lot: diamond certification.

What Is Diamond Certification?

Diamond certification is a system created by the Gemological Institute of America (GIA) to evaluate the quality of a diamond based on the 4Cs—carat, color, clarity, and cut. Diamond certification is also referred to as diamond grading and it is highly recommended that couples only buy certified diamonds.

Not only does diamond certification determine the quality of a gem, but it then communicates the diamond’s qualities in a way that helps consumers understand what they are buying.

Advantages of Buying a Certified Diamond

One of the top advantages of buying a certified diamond is precedent. The Diamond Grading Report is the premier credential of a diamond’s authenticity and quality, especially when buying engagement rings.

This common language and the widely accepted methods, and best practices to grade diamonds add a very important consumer-protection element to the way diamonds are bought and sold. Reports give people confidence in their purchases because they have an independent and impartial evaluation of the diamond’s quality.

Understanding the 4Cs: The Ultimate Diamond Guide Cost of Certification

The price of grading report varies depending on the type of stone, its carat weight, and the service requested. For D-Z diamonds, the basic grading service is about $30 for a quarter-carat diamond to about $85 for a one-carat stone, with the fee increasing based on weight and the service. 

How to Read a Diamond Certificate

There are a few things to keep an eye out for on a diamond certificate:

• The date the diamond was graded
• The report number
• Shape and cutting style (i.e. round brilliant)
• Measurements
• After those details, the certificate will list the grading results for the carat weight, color grade, clarity grade, and cut grade.
• Additional grading information includes polish, symmetry, and fluorescence. The certificate also offers a profile view of the diamond with exact proportions as well as clarity characteristics. 

Types of Diamond Grading Systems

While the GIA grading system is among the most well-known and trusted, there are also a handful of other certifications to keep an eye out for, including AGS, IGI, EGL, GSI, and HRD.

Since some aspects of diamond grading are subjective (like color and clarity), it’s best to compare stones that have all been evaluated by the same entity. For example, the GIA does not grade diamonds with the same approach as EGL.

American Gem Society (AGS)

Founded in 1934, the American Gem Society was created by a group of jewelers to “protect the jewelry-buying public from fraud and false advertising.” They evaluate cut, color, clarity, and carat on a 0-10 scale—the highest grade is zero and the lowest grade is 10. AGS is now joined by three thousand members including jewelers, retailers, and suppliers, and is considered a reliable source for diamond certification.

International Gemological Institute (IGI)

The International Gemological Institute has been around since 1975 and has 18 laboratory locations around the world. IGI evaluates loose diamonds as well as finished jewelry pieces and was the first gemological institute to fully grade lab-grown diamonds, starting in 2005.

European Gemological Laboratories (EGL)

Reports from European Gemological Laboratories typically include carat weight, clarity grade, color grade, cut (shape and style), finish, fluorescence, plotting, and proportions. They are also often considered looser with their grading standards. 

Gemological Science International (GSI)

Gemological Science International was founded in 2005 and grades both natural and lab-grown diamonds. Their laboratories employ advanced technology and instruments to capture a diamond’s light performance and reports include information regarding shape, weight color, clarity, fluorescence, polish, symmetry, measurements, cut grade, and plotting diagram.

Hoge Raad voor Diamant (HRD)

Hoge Raad voor Diamant issues certificates for diamonds and gemstones primarily in Europe and is in Antwerp, Belgium—a geographical location that is synonymous with diamonds. The company uses what they refer to as a “double coding system” and provides reports for natural, lab-grown, and treated diamonds.

What to Look for When Grading Diamonds Consistency and strictness

You want the lab that’s evaluating diamonds to treat all the gemstones they see the exact same way. Strictness also ensures you are getting what you paid for.

Is a Diamond Certificate Necessary?

Yes! There’s no way to know what you’re buying without a qualified, trusted entity to evaluate your diamond. Do not buy a polished diamond unless it has a certificate.

Eng. Clever Sithole.

Career Gemmologist

GIA Accredited Jewelry Professional

CPAA Certified Pearl Specialist