Are Costco Diamonds GIA Certified? – Detailed Answer in 2024

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 Costco is one of the biggest home goods retailers in the US, and you can find just about anything and everything from Costco, with jewelry being one of the things sold in the store.

But then, while they offer excellent jewelry options, including diamond jewelry, the brand hasn’t had the wildest success when it comes to offering diamond pieces of jewelry, especially after they stopped selling GIA-certified diamond jewelry. But some of the pieces are certified.

So, what does this mean about Costco diamonds, and are the diamonds certified by the GIA? And with Costco’s standards and values having gone down over the years because of the relaxed standards and the fact that the GIA doesn’t certify all Costco’s diamonds, understanding what they offer right now is important in guiding you to make the right decision.

Well, keep reading to learn more about Costco’s diamond jewelry.

Oh, we also talk about this topic here:  Tiffany Vs. Costco Diamond Ring-Which One Wins? Read here for more! 


About Costco diamonds jewelry

Costco’s history precedes them, and this wholesale corporation stands out quite well because it has been able to build a fantastic and one of the most successful business models.

are costco diamonds gia certified

Costco’s model features a system in which they provide bulk products with very thin margins. And for this major retail chain, their services are always second to none.

The company also boasts one of the most legendary return policies. And so, for many years now, Costco’s very excellent reputation is why they are known for providing some of the best kinds of jewelry.

Overall, if you are looking for the very best options of engagement rings, and most importantly, a store that offers low pricing overall for their diamond engagement rings, not to mention an in-person shopping experience, Costco could be the very best option for you.

And so, if you’re looking for decent-quality diamonds that will give you great value for your money, then Costco could be ideal. All you’d have to do is make sure that the said diamonds are GIA-certified – this is, unfortunately, this is not always the case with Costco’s jewelry. And in the following sections, we’ll highlight some of the things you should be expecting from Costco’s jewelry.


  • Variation in the quality of Costco’s diamonds

One thing that we are certain about when it comes to the quality of the engagement rings sold by Costco is that while Costco offers guarantees on all the diamonds, they sell, noting that all their diamonds are either VS2 clarity or I color, or an even color grading, research shows that most of Costco’ diamonds fall into these two color and clarity grades, which equals some of the most decent diamonds, and so, worth the price tag on each of them.

are costco diamonds gia certified

The VS2 clarity diamonds, for example, are regarded as eye-clean diamonds, with the I color diamonds pretty much in the near-colorless range for the diamonds. However, these diamonds would still look a little white. These diamond grades result in good value diamonds, and though they are low-priced, this stone still looks flawless to the naked eye.

But there is one catch for the diamonds offered by Costco, the cut, and the cut’s grading. While the cut of the diamond is one of the most important factors in diamonds as it determines the shine and the sparkle of the gemstones, Costco offers no cut grading for their diamonds, so determining the actual quality of the stones can be a bit of a challenge.

And so, it means that if you are looking for affordable, premium, or super-high-quality diamonds, you will not find them at Costco.


  • The diamonds are not all GIA-Certified

One of the biggest reasons for contention where Costco’s diamonds are concerned is their certification, or rather, lack of certification of some of the diamonds by the GIA.

And though Costco claims to use GIA’s diamond grading standards – GIA is the Gemological Institute of America and the world’s leading diamonds lab, thanks to their very high standards. For the consistency of their reports, not all of their diamonds have the GIA certification.

Instead, Costco claims to have a team of in-house GIA graduate gemologists who inspect all their diamonds to ensure that they meet their quality standards. But that is not the only disappointing bit of news.

The rings with less than a carat of diamond don’t come with a certification document, but instead, a Costco Article of Description stating the diamond’s details is incorporated. These diamonds also have no-cut grade.

However, you will get a GIA grading report for the diamond if it is more significant than a 1-carat weight. You will also get jewelry or gemological report from Costco for the bigger diamonds. And in other cases, the diamond jewelry would have an IGI certificate incorporated. The IGI is just another diamond grading lab.

are costco diamonds gia certified

So, it is a big challenge that the Costco diamond jewelry options that are less than 1-carat weight are not certified by the GIA. The absence of this kind of official certification for the smaller diamonds and the fact that no other lab certifies these diamonds means that you will be forced to trust Costco’s in-house grading system, which is, unfortunately, not reliable or proper proof for the diamond’s quality.

The accuracy of Costco’s grading is also unknown and largely untrustworthy. Note that it is rather costly to get diamonds certified by the GIA.

In an attempt to keep costs low and the price of diamond jewelry low, it may make sense that Costco’s opted to use their certification system for the smaller stones. Consequently, this has resulted in the lower prices of Costco’s diamond jewelry.

But for anyone keen on spending their hard-earned money on diamond jewelry, an official certification of the diamonds is very important, regardless of the size of diamonds.

And so, Costco is slowly becoming an unreliable jewelry seller, especially for the diamond jewelry options, by forfeiting the expected standard certification option for the smaller diamonds.


  • The diamond engagement rings are all pre-set.

When it comes to finding the perfect diamond ring for your particular person, there are features that you always wish to have as custom, especially because you may want different diamond cuts or just the setting.

And so, with Costco’s pre-set engagement rings, you have zero customization options, which is not ideal for most people.

This makes it virtually impossible for you to find the perfect engagement ring, but it also means that there is a high chance of ending up with the desired ring in the wrong size or diamond shape.

So, if you prefer the rose gold metal for the ring rather than white gold, this might not be something that is guaranteed at Costco.

The ring might be off a size even with the right metal setting. So, without any guarantees of the features of the rings versus what you are looking for, buying jewelry from Costco is always a huge risk.


  • Limited choices

Costco fails to give its customers options to choose from; this brand also offers a minimal range of options for diamond jewelry. In fact, their selection of engagement rings is nothing short of tiny.

And on the website, for example, you will have access to only 150 options of diamond engagement rings, while the local stores may or may not have as many or better selections.

In some cases, you will find varieties of rings that only have 2 choices for you to choose from, for example, the rose gold rings.

So, you may have to look for the engagement ring from alternative, more specialty stores like James Allen or Blue Nile, which often have hundreds of options that you get to choose from, not to mention the best customization options.


Are Costco diamonds GIA certified?

are costco diamonds gia certified

Some, and not all of Costco’s diamonds, are GIA-certified. More specifically, diamonds with less than one carat in weight are not certified by the GIA but by Costco’s in-house team of GIA graduates.

And for these diamonds, you will receive the Costco Article of Description only – this document details the diamond’s primary features, but not the cut. This documentation is also not a certificate.

However, all diamonds that are 1 carat or larger have the GIA Diamond Grading Report/ Certificate that specifies the features of the diamond. But it doesn’t list its monetary value.

You would have to contact the certification company for an insurance appraisal – for Costco, the purchase price is documented as the ring’s insurance replacement value.


Do Costco diamonds come with a GIA certificate?

Unfortunately, this retail megastore that also deals in some great jewelry options does not offer certification for its diamonds. And in many cases, the diamonds below 1 carat will only feature an article of description for the diamond jewelry rather than a certificate.

Diamond jewelry that is 1.00 carats or larger also lacks a certification, although these feature the GIA Diamond Grading Report, which somehow makes these rings GIA certified rings.

And because of the great significance of the GIA-certified diamonds. No one wants to spend all that money on a diamond ring, only to go home with a report and no official certification. The GIA certificate, for example, is ideal when you need to ensure the diamond ring or if you plan to sell the ring later.

The fact that the 1.00-carat weight of the diamonds is not inclusive of the ring’s band and setting weight means that many people buying jewelry from Costco cannot afford such rings.

Does Costco sell lab-grown diamonds?

While Costco sells lab-created emeralds and other gemstones, the store insists that its diamonds are all-natural or mined and untreated rather than lab-created.


Are Costco diamonds good quality?

Now that we have looked at everything necessary for us to know about the certification of Costco’s diamonds let’s take a look at the quality of Costco’s diamonds and if these diamonds are good quality stones worth investing in.

are costco diamonds gia certified

Overall, Costco’s jewelry stands out because of the low prices. Still, there is something else that keeps Costco’s diamond jewelry options in such high demand – this is the fact that the diamonds boast the highest quality and level of craftsmanship and quality.

Of course, the lack of customization options is a huge challenge for these gemstones, and you may not find something that matches your taste or individuality. Still, the diamonds are essentially well made, and you won’t have to worry about the stones falling out soon after purchase.

4Cs for Costco’s Diamonds

Essentially, most jewelry retailers use and abide by the standardization metrics set by the GIA for diamonds and so employ the 4Cs – Color, Cut, Clarity, and Carat weight to determine the quality and the value of the set stones. And this is important because these 4 elements of the diamonds determine the diamond’s quality.

Cut, for example, is very important because it guides personal style and taste while also pointing to the brilliance and the sparkle of the stone.

Clarity is equally important as it points to the purity level of the gemstone, with designations like VVS1 or VS1 referring to Very, very slightly included, and very slightly included. Costco notes that their stones’ lowest clarity level is VS2, and the color grade I.

According to the 4Cs, the color of diamonds ranges from D to Z, with D being the best color quality that is pretty much colorless. Their diamonds are VS2 graded for clarity,

And in terms of the carat weight, only diamonds above 1.00carat are graded by the GIA, which can be used to ensure fine jewelr



If you are looking for the best quality diamond jewelry, make sure that they are GIA-certified, regardless of their carat weight.

Unfortunately, Costco only has GIA certifications for their diamonds that are 1 carat or larger and no certification for the smaller diamonds.

Read more diamond topics here or here

Hey! I finally find the Answer!