What Is a Certified Diamond?

What Is a Certified Diamond?

round-cut diamond halo ring on white background
Diamonds are stunning in any piece of jewelry, and even though all diamonds are precious, not all diamonds are equal in terms of value. Certified diamonds are a good investment because experts verify their gem grades. Whether you're looking for a diamond engagement ring or investing in diamond jewelry for yourself, understanding certified diamonds is helpful during the shopping process.
round-cut diamond halo ring on white background

Certified Diamonds vs Non-Certified Diamonds

A certified diamond is often a safer purchase because you know its precise value. Certified diamonds have been examined by an unbiased laboratory and graded on the quality of their cut, color, clarity, and carat weight (these criteria are known as the four Cs).


How Are Diamonds Certified?

Clarity refers to the number of flaws within the diamond — tiny inclusions leftover from the creation process. Carat weight refers to how heavy the diamond is and doesn’t necessarily reflect the diamond’s size. Color ratings are based on the hue and tint of a diamond. White diamonds are uncolored and clear, and they are often the most sought after.

On the other hand, naturally tinted diamonds, also called fancy diamonds, are often prized for their color intensity, which can raise their cost and value significantly. Cut refers to how well a diamond has been faceted to refract light. This grade takes things like symmetry and reflectiveness into account. To learn more about the criteria used to certify diamonds, check out our Diamond Buying Guide.


Who Certifies Diamonds?

There are a variety of independent laboratories that examine and grade diamonds, but the most reliable evaluations come from reputable certification institutes. In the United States, the most used and trusted laboratory is at the GIA, or Gemological Institute of America.

The GIA is responsible for establishing the four Cs, the most widely used diamond-rating scale throughout the world. The American Gem Society (AGS) is another trusted institute that also uses the guidelines set by the GIA in their certification process.


Why Buy a Certified Diamond?

A diamond that has been evaluated by a certification institution is assigned a model number and a certificate that verifies its grades. If you plan on purchasing an expensive diamond, it’s a good idea to look for a diamond that has been certified by one of these institutes. If you have a certified diamond already, you can arrange for an independent appraiser to verify that the diamond matches the certificate.

It’s important to do plenty of research before selecting a diamond appraiser or institute to make sure their information is reliable and that they don’t have any ties to vendors or other interested parties.


How Do I Select the Right Diamond?

As you search for the perfect diamond or piece of jewelry, it’s a good idea to consider which grades are most important to you. Take some time to rank the four Cs so that you know what to look for on a certificate. If money isn’t a constraint, you may opt for a large diamond that’s both colorless and without flaws. However, if you’re searching for a diamond that fits a tighter budget, your personal preferences are the most important factors to consider.

Large diamonds with a few small flaws can still make a grand statement, while a small, flawless stone will add resplendent beauty and shine to any ring setting. When you know which certification aspects you most value in a diamond, it will become much easier to find the perfect stone for your jewelry.


Disclaimer: Overstock carries a wide selection of certified diamond jewelry. Although some diamonds on Overstock.com have not been certified by the GIA, every diamond we sell is 100-percent authentic.