What Does it Mean to Buy a Certified Diamond?

Author David Millette
Date Feb 15, 2021

Certified DiamondWhen you are purchasing a diamond, there are many factors that will determine the price you pay. The most important of these factors are the four C's of diamonds which consist of cut, color, clarity, and carat weight.

Some of these attributes are easier than others to grade. Carat, for example, is just a measure of the diamond's weight and there is no disputing the measured result. Clarity and color, on the other hand, are graded on a scale that is much more subjective.

Unless you have extensive gemology training, you probably won't be able to determine the grades of a diamond yourself.

Purchasing a "certified diamond" is one way to check if a diamond is fairly priced and is a good quality stone. Certified diamonds have been evaluated by an independent lab and come with a universally-accepted grading report.

Before you commit to buying your diamond, let's take a look at what grading reports offer and why shopping certified diamonds is the safest option:

What does a certification provide?

When you send your diamond to get certified, it will be inspected by a team of gemologists who will individually grade it. They will report on the cut, measurements, carat weight, color grade, clarity grade, polish, symmetry, fluorescence, and proportions of your diamond. Any inclusions will be marked on a clarity diagram so they can be located. The report will also certify that the diamond formed naturally and was not manufactured. All of the grades will be averaged, and the information is then sent back to the owner along with the diamond.

There are many labs that will certify diamonds, but they all certify them in the same way. The main differences between these labs is how strictly they grade and their reputation. Both of these factors are usually determined by their standards, plus the level of training that their employees receive.

Who certifies diamonds?

The Gemological Institute of America, or GIA, originated the practice of diamond certifications and has been the industry leader since its creation. They have the world's pre-eminent gemological laboratory and research center, which allows them to provide accuracy and precision in their GIA report. Also worth noting, GIA is not in the business of selling diamonds nor are they affiliated with anyone who is. This assures the customer that they are receiving an unbiased grading report.

GIA reports using the International Diamond Grading System, which they invented. GIA grades a diamond's color on a 23 grade scale, ranging from a D (perfectly colorless) to Z rating, and clarity in an 11 grade scale, ranging from flawless to I3 (heavily included). This scale is the standard for grading diamonds and is nearly universal.

Founded by the same man who started GIA, the America Gem Society (AGS) is also considered to be an industry leader in diamond certification. AGS reports are done in the same way as GIA reports and are viewed as equally credible. You can't go wrong with a certification from either of these labs as their standards for diamond grading are the top in the industry. All other grading labs, such as EGL and IGI, use a lower set of standards which means that they give more generous grades compared to GIA or AGS. In other words, a diamond that the GIA or AGS determines is a G color / SI1 clarity might be graded as an E or F color / VS clarity by a lab with easier grading standards. Same diamond, different grade because of different labs!

Where to buy a certified diamond?

Along with certifying diamonds, AGS has built an elite group of retailers. AGS members are held to the highest standard for ethical business practices.

To become a member of the AGS, a store employee or owner must have completed a graduate program at the Gemological Institute of America. Furthermore, they must complete continuing education and re-certification programs every year through AGS. This guarantees that the business will always be knowledgeable in the field and be able to offer the most fair prices to its customers.

Other notable requirements of AGS affiliates include:

  • The firm must possess a Binocular Microscope to allow consumers to closely examine each diamond
  • The firm must not misrepresent its merchandise in any way
  • The firm must carry a representative stock of gemstone jewelry merchandise in keeping with the market area


To see a full list of the credentials needed to become a member click here.

The qualifications to become an AGS member are difficult for a reason. This association was established to protect the consumers. A company that doesn't believe in supporting this cause will be denied admission. That is why only one in every twenty jewelers can call themselves a member of the American Gem Society. These retailers are sure to have certified diamonds and sell them at a fair price.

As a member of AGS and GIA, we focus on selling beautiful certified diamonds at fair prices. Are you interested in looking at certified diamonds? Make an appointment today with one of our experienced diamond experts!

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