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Costco Diamond Rings: Our 2024 Review

Is Costco a good place to buy diamonds or diamond jewelry?

By Mike Fried,
Overall Score:2.172 Rating2 Rating
Price:3.53.5 Rating3.5 Rating Selection:11 Rating1 Rating Customer Service: 22 Rating2 Rating
  • Great return policy

  • Non-existent service
  • Poor selection
  • Mediocre pricing
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Costco engagement rings are surprisingly high in quality and craftsmanship, but there limited range of styles and supply pose an issue for consumers. I have 20 years of experience in the diamond industry. My first 7 years I spent working at a major diamond importer, and I remember when we tried working with Costco. Their quality parameters were surprisingly strict. Costco was adamant that all diamonds are within very tight cut parameters to ensure they would be brilliant.

Over the last 12 years, I’ve secret shopped thousands of retail locations around the world. I’ve been to all of the major diamond jewelry retailers (jewelers and big department stores that also sell engagement rings) many times over. Costco is certainly lacking in many respects, but the quality of their diamonds and jewelry is not anything to worry about.

Costco is the place for everything you need in your home. Toilet paper, TVs, books, pickles and the best slice of pizza and soda you can get for a buck fifty. Unless you live in a small apartment, or far away from a large town/city, Costco plays a pretty large role in your life. Growing up in the suburbs, we used to shop there at least once a month. But is Costco the right place to purchase a diamond engagement ring? That is the question we are going to answer in this review.

Costco has a reputation for high standards of quality under its Kirkland brand. They have a fantastic return policy. Do those factor into their jewelry? Over the last 12 years, I’ve secret shopped Costco’s engagement rings many times. I’ve even purchased and returned a couple of diamond rings. I’ve also looked at Costco’s online diamond jewelry offerings extensively.

This review of Costco diamond engagement rings will cover those secret shopping trips. We’ll talk about their selection of engagement ring styles and the quality of their diamonds. We will also discuss what you are missing out on by not getting your engagement ring from a proper jeweler.

To help you with the diamond buying process we lean on our expertise and experience. The author of this article, our CEO, Mike Fried has over 20 years of experience in the diamond industry. Mike started from the bottom, sorting and evaluating hundreds of thousands of diamonds to learn every facet (pun intended) of diamond quality and value. Mike followed that up by spending years buying and selling diamonds on the wholesale market as well as selling tens of millions of dollars worth of diamonds to diamond retailers.

Here’s what we’ll cover in this article:

Reaction video of Costco rings (May 2023)
Background of Costco Jewelry
Costco diamond quality
Costco engagement rings
Costco’s lack of customer service for engagement rings
Are Costco diamond rings good value
Secret shopping in May 2022
First secret shopping Costco diamonds
Bottom line recommendation

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Reaction Video of Costco Diamond Rings in May 2023

My latest secret shopping trip found me in a Costco in the St. Louis suburbs. As we discuss at length below, the selection at Costco is extremely limited. I looked at their platinum solitaire setting with a round diamond. Their standard one carat version is I color and VS2 clarity and cost $5,999.

The quality of the diamond was right in the sweet spot for the 4Cs and was GIA certified. Ignoring the lack of variety, the real issue was the price. Take a look at this GIA certified 1 carat I VS2 from James Allen for $3,480. Add it to this platinum solitaire setting and your total cost is $4,300 for an identical ring. That is 30% less than Costco and you are getting all the extra value of ordering from a jeweler (as we discuss below).

Background of Costco Jewelry

There is no reason for me to bother with a history of Costco — the company’s reputation precedes them. Speaking personally, I love Costco. My family and I have been long time customers of Costco and I admire the company’s philosophies.

Costco Wholesale Corporation has built a fantastic business model of providing bulk items with razor-thin margins. For a major retail chain, their service is second to none. They also have a legendary return policy.

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Some of you may be a bit surprised to learn that Costco has a jewelry department. In fact, they have made some pretty big sales of diamond rings like this $600,000 sale reported by JCK Online. Costco used to have a great reputation for jewelry. Speaking from experience, from the perspective of a supplier, I used to be impressed with their quality control. Unfortunately, the quality of their jewelry has seemed to have slipped over the last few years.

When I started with this site, I would get emails from readers asking about Costco diamonds. They used to have diamonds with GIA certification. As you will see below, this is no longer the case.

Costco Diamond Quality

This is where Costco shines. Costco is famous for the quality of their products. For many of their Kirkland brands, they have major brands to make the products for them. The quality of their diamond jewelry is no different.

Ringo Approved Eye Clean Diamonds

What is Ringo?

As I mentioned above, Costco has very strict quality parameters. When I was trying to sell diamonds to Costco (during my days working for a diamond manufacturer), their cut parameters were very strict. This ensured their diamonds would have as much fire and brilliance as any retailer out there. We also agree with their color and clarity parameters: I+ and eye-clean VS2 is a great sweet spot of quality.

So before going into their negatives, I wanted to make sure to highlight their positives.

Costco Engagement Rings

This is where Costco starts to falter. The craftsmanship of their jewelry is top notch, but they simply do not have enough variety of setting styles to satisfy most customers. Sure you can order different shape diamonds online from them and get a ring size other than 7 from their website. But if you don’t like their three of four setting styles, you are out of luck.

A solitaire engagement ring from Costco
Costco solitaire engagement ring

Here are a couple of ways their setting selection:

  • No options if you prefer the look of yellow or rose gold.
  • Can’t switch from platinum to white gold which would be advisable for engagement rings under $10,000.
  • Unable to get a solitaire in a basket setting (that is set lower) if you don’t want the diamond sticking out.
  • Lack of variety in setting styles if you prefer anything but the simplest solitaire, halo, three stone or pavé setting.
  • Sizing difficulties.

Costco’s Lack of Customer Service for Engagement Rings

Let’s face it, even with getting help from The Diamond Pro, you still may have questions when purchasing a diamond. You may want some advice on care or what setting style to go with. I love the people who work at Costco. But they are not trained to help you with jewelry. It’s simple as that.

The employees at Costco are there to open the case (they need a manager to do so). Nothing else. Any online jeweler or physical jewelry store will give you a better buying experience than Costco.

Are Costco Diamond Rings Good Value

Unfortunately, I just don’t see any reason to purchase an engagement ring from Costco. The value just isn’t there. Above we discussed how you can purchase an identical 1 carat solitaire setting from an online jeweler like Blue Nile or James Allen for 30% less.

Below we discuss other secret shopping experiences we’ve had. I once purchased a 0.70ct showed that you can save 30% if you went with this 0.70ct I color VS2 clarity excellent cut from Blue Nile and paired it with this solitaire setting.

Those savings, while significant, are not as dramatic when comparing other brick-and-mortar retailers to online retailers. Given Costco’s lack of diamond service, however, I think that drop is very significant.

You don’t have service for sizing or any sort of warranty, and there is a very limited selection of setting/diamond options. While you can do some research and due diligence on your own, there is no personal service at Costco.

Secret Shopping Costco Diamonds in May 2022

We’ve done thorough secret shopping both online and in person at Costco. We periodically revisit our reviews and we secret shopped Costco at their Lynnwood WA location in May of 2022.

The experience was comparable to our experiences below. The person working the TV section came over to open the cases for us. He was very nice, but wasn’t helpful (they are not trained jewelry professionals).

Costco store in Lynnwood WA
Costco store in Lynnwood WA

We were unable to get any decent information about the jewelry that wasn’t printed on the display. For that reason, we won’t do specific comparisons of the jewelry we saw to their competitors. We have done that previously and you can read about that later on in this article.

Their selection is very limited, but the diamonds they do have are of excellent quality. Overall you don’t go wrong purchasing a diamond at Costco but you have more variety and options, as well as superior service and value shopping online at a reputable retailer like James Allen or Blue Nile.

First Secret Shopping Experience

The Ring from Costco - Click to Enlarge
The ring from Costco – Click to enlarge

Unlike our more recent secret shoppings, we went with a 3/4ct diamond ring, which meant the diamond did not have a GIA certificate. Costco claimed the diamond was an I color, VS2 clarity. While it was definitely VS clarity, I personally thought the diamond was in the J color range. I’m willing to take their word for it though

To their credit, this was a well-cut diamond (I can’t give specifics as it was mounted already) and the clarity grade was fair. However, the diamond was a J color, not the I color they claimed it to be. Learn more about cut, color, and clarity in our useful guide on the diamond 4 Cs.

The actual setting, while simple, was fantastic. It was a classic four-pronged platinum solitaire. The craftsmanship and quality were on par with any company that I would entrust. Overall, the ring I purchased was a nice choice, right in line with our recommendations (an eye-clean, well-cut J color for a solitaire).

Costco Appraisal - Click to Enlarge
Costco Appraisal – Click to Enlarge

Though the ring is nice, the value is just not there. The ring cost $3,503.99, including tax. Any way you cut it, the price is not justified by the product. Two comparisons can be made here, one based on my grading (J-VS2) and one based on their grading (I-VS2). We already discussed the price comparison above.

Bottom Line Recommendation

Costco has fundamental drawbacks inherent to their business model. They have no service in the store and their selection is very poor. Contrast their selection with the thousands of possibilities you can see at a jeweler. Take James Allen’s engagement ring section, where you can look at endless diamond and ring setting combinations, for example.

As you will read below, the prices aren’t too hot either. Here is a stunning 3/4ct diamond from Blue Nile and a beautiful ring that cost almost 30% cheaper than the ring we found at Costco. 

With their drop in quality/value paired with their lack of service and selection, you should not be buying diamond engagement rings from Costco. You will be much better off buying your diamond from a top online dealer like James Allen or Blue Nile. If you prefer some personal help in finding the right ring, feel free to contact us.

Note: Since it has been one year since we secret shopped Costco, we are using the updated prices from their website and a more current diamond from James Allen).

FAQs About Costco Jewelry

Is Costco a good place to buy jewelry?

While Costco does offer high quality and craftsmanship on their jewelry, they tend to have limited supplies and styles. In addition, the salespeople are not trained in jewelry, making it difficult to get any additional information on specific pieces.

What quality diamonds does Costco sell?

Costco claims to sell diamonds of a VS2 clarity grade and I color or higher. In our testing we have seen this to be accurate. The cut parameters of Costco diamonds are also generally of very high standards.  

Can Costco jewelry be returned?

Yes, Costco has a return policy on purchased jewelry. Certified diamonds must be returned with the original GIA or IGI certificate. According to Costco, Diamonds over 1 carat will receive a credit memo.

James Allen James Allen is the leader in online diamond sales. Their imaging technology is the same as inspecting a diamond with a jeweler's loupe. They have the largest exclusive loose diamond inventory online and fantastic prices. They also have the nicest collection of lab-created diamonds online.
What we love about them:
  • No questions asked returns within 30 days of shipment. James Allen will send you a paid shipping label to return the ring.
  • Lifetime Warranty
  • Free International Shipping
  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisals
  • One free resizing within 60 days of purchase
  • Free ring inscriptions
  • Best-in-class high quality imagery of all diamonds in stock
  • 24/7 Customer Service
  • Best-in-class packaging
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Blue Nile Blue Nile is the largest and most well-known internet jewelry seller. They have a very large exclusive online inventory. Their high-quality images are catching up to James Allens' and their prices are amazing. 
What we love about them:
  • No questions asked returns within 30 days of shipment. Blue Nile will send you a paid shipping label to return the ring.
  • Lifetime Warranty
  • Free Shipping
  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisal
  • One free resizing within the first year of purchase
  • High quality images of about half of their diamonds
  • 24/7 Customer Service
  • 100% credit towards future upgrades (must be at least double in value)
  • Best in class fulfillment
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About the author

Mike Fried Mike Fried Mike Fried has over 25 years experience in the diamond industry working with Leo Schachter Diamonds, Moshe Namdar Diamonds, and joining The Diamond Pro in 2007. He is recognized as an industry expert and has been quoted in publications such as Us, People, Page Six, The Next Web and more.

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