When asking — and clearly answering — whether a specific Costco diamond is worth buying, I love using data and hard figures. I prove my case with numbers. I compare Costco diamond ring offers to rings from other highly reputable online diamond ring retailers. James Allen is my go to source. They usually win, but not always.
What about this Costco 1-Carat Round Brilliant Diamond Flanked by Two 0.15-Carat Baguette Diamonds, in Platinum? (That makes a total of 1.3 carats, of course.)
How will it compare in value? Let’s dive in.
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Bottom line (spoiler alert): You can get a diamond ring with the same specs (actually better) from James Allen for about $1,190 less than Costco’s price. (Or even $3,420 less.)
You can get the same design of setting (or very similar, in fact in my opinion it’s better).
In the world of diamond retailers, you can save thousands. You may think “You get what you pay for.” And that’s certainly true.
- But sometimes you’re paying for name brand (not necessarily a better diamond) such as Tiffany. Not worth it, in my opinion.
- And sometimes you’re paying for a lot of real estate for big box stores, such as Costco. Who needs that?
- When you look for diamonds that have diamond certificates or grading reports, you know what you’re getting. So you don’t have to take a retailer’s word for it that a much more expensive diamond is somehow magically better than a less expensive one.
As for this particular Costco offer …
- You can definitely get a better quality center diamond. (One that has a certificate from the IGI (International Gemological Institute). (The center diamond in this particular Costco ring does not have any diamond certificate, that I could find, from any 3rd-party lab.)
- Plus, you can get virtually the same baguette diamonds (the two diamonds on either side of the center diamond). (The James Allen ring I’ll show you has two 0.12-carat baguette diamonds.)
- All for only about $5,810.
- I’ll prove all that in this article. (And it’s not that long. You got this.)
To get the James Allen deal, scroll down to the section of this page that shows you how easy it is to build this ring at James Allen.
Costco’s offer: Round Brilliant 1.30 ctw VS2 Clarity, I Color Diamond Baguette Platinum Ring for $6,999.97
You can see it live, as long as it’s in stock, as item number 992832 at Costco.
Costco’s Lack, in This Case, of a GIA (or other lab) Diamond Certificate
A 3rd-party lab-issued diamond certificate is always expected for an expensive diamond. (Anything more than an accent diamond, or cheap diamond jewelry.)
Often Costco does have such a certificate for a diamond ring. If they do, it’s always the first thing noted under the “details” section (pictured above).
This $7K price range certainly should get a certificate for the diamond.
Especially because it is a round brilliant cut, this lack of a diamond certificate is a huge red flag.
(A diamond certificate is issued for many kinds of shapes of diamonds. But a Round Brilliant shape should get a diamond grading report. The Round Brilliant shape, or cut, is the only cut that gets a diamond grading report. Why? It’s complicated. But the bottom line is that it’s the only shape studied well enough that gemologists can grade massive numbers of them for the cut quality that results in sparkle and fire.)
TL;DR version of this section:
Lack of a diamond grading report (from GIA, IGI, or AGS), or even a diamond certificate of any kind (which would at least state some basic facts about the diamond, even if doesn’t grade it), is a huge red flag.
Probably it’s an ok diamond? But that uncertainty is nowhere near good enough to justify spending $7K on a diamond.
You’ll see that James Allen of course also offers an IGI diamond grading report. (You can also find, at James Allen, similar diamonds with a GIA grading report, which is the industry “gold standard.”)
Shape
The shape is Round Brilliant Cut.
Carats
The center diamond is 1 carat.
Total carats, including the accent diamonds and the center diamond, is 1.30 carats. So, we can know that the two “baguette” diamonds weigh a total of 0.30 carats. That means they weigh 0.15 carats each.
(A “baguette” diamond is a long flat diamond, like a French baguette, employed to flank a center stone in this classic design.)
Clarity is VS2
That’s not a terrible clarity score, especially for a round brilliant cut. (Because a round brilliant cut creates so much sparkle and fire that it can obscure the inclusions (flaws) in the diamond.)
However … it all depends on where the inclusions (flaws) are located! If they’re located right near the top, the diamond is essentially ruined. If they’re located deep in culet (bottom), or otherwise obscured by a prong for example, they’re no problem.
But you don’t know, without a diamond certificate or diamond grading report, where the flaws are. (A diamond report would diagram exactly where the flaws are. Also, at James Allen, you can look at your specific diamond using James Allen’s easy to use 3D imaging. And so you can see it directly. You can’t do either at Costco, with this particular diamond.)
Consequently, we can’t say with any certainty whether “VS2” means the diamond is ok for clarity.
And uncertainty is worse than that, although I hate to say it … Here’s the thing:
- Unless a 3rd-party lab is vouching for a diamond’s clarity scores, or color, you don’t really know.
- Who says this Costco diamond is VS2 Clarity?
- Was it a gemologist employed by Costco? Was it just a salesperson? Someone with expertise or no expertise? Someone with experience?
See? That’s why a diamond certificate or grading report from GIA, IGI, or AGS is so important. They’re done by trained gemologists at 3rd-party labs who grade diamonds without knowing who is selling them.
Color is I
That’s not a terrible color, for a round brilliant cut. The sparkle and fire will obscure and hide some color.
(Again, that’s supposing the color grade here is done accurately, by a trained gemologist. Which is assuming too much, for $7K, and no diamond certificate.)
Another problem with lack of info, related to color: Costco doesn’t tell us what color and clarity grades the baguette diamonds have. What if they’re too yellow? What if they’re a better color than the center diamond, and make it look yellow by comparison?
The lack of info is really disconcerting to an experienced diamond shopper. Costco sometimes has good deals. They sometimes give good information (in GIA diamond certificates or grading reports). But this is not one of those times.
Cut Quality
Cut Quality is a spec that the GIA grades for round brilliant diamonds only. It’s super important. It boils down to: How well did the diamond cutter proportion and cut this stone, to make it sparkle?
All kinds of art and science enter into this question. And if you don’t have a diamond grading report saying that it’s a certain cut quality, then be very leery of buying that diamond.
Why? Because you could a real dud on your hands. A diamond that doesn’t sparkle, because it was cut slightly crooked. Or it wasn’t proportioned just right.
Metal
The metal is Platinum
The James Allen Offer. Same specs or better. Much better info due to a grading report. For $5,810.
Notice that the center stone is of the same quality: VS2 clarity, I color,
Note also the “Excellent” cut quality! That’s a real gemologist’s opinion. Straight from the IGI. That’s an unbiased, 3rd-party lab’s grade. So it means something.
Furthermore, when you look at the product page of the setting alone (the ring itself, with the baguette diamonds, but not the center diamond yet), you’ll see that it tells you the color and the clarity grades of the baguette diamonds!
That’s huge. It means you can more confidently rely on the colors of all the stones matching, going together.
“Great! But um … How do I get this James Allen Deal? How do I build that ring?”
It’s easy.
- First, select this setting as your setting (the ring itself).
- Second, go to James Allen’s diamond inventory search engine and simply set your sliders as shown in the image below.
Then just select diamond that you like. And add it to the ring. Simple!
Then you’ll see the deal (or a very similar deal) to the $5,810 deal pictured up there, a few images up.
Want to save even more and get the same quality of ring for $3,580? (That’s almost half price of the Costco ring!) Then do this.
- Select the same setting as before.
- At the James Allen diamond inventory search tool, choose Lab Created instead of Earth Created. (See the image below.) (Lab Created diamonds are 100% identical, exactly the same substance, as Earth Created diamonds. They’re not fake. They’re real. They’re just made in a lab mimicking conditions deep inside the earth.)
- Then select a Lab Created diamond you like and add it to the setting. It’s tons less money.
Here’s the total price of the setting and the Lab Created diamond, all together: $3,580. Same quality (actually better). Same everything.
Congratulations
You avoided a Costco diamond that, in my opinion (and I think I’ve laid out the numbers, the data, pretty well here) is not worth it.
You can get a diamond with a certificate / grading report, and baguette diamonds with information on them, and a setting that is at least as good as the Costco if not better, for far less than you would have paid the big box store.
It’s easy to get great deals on better diamond jewelry — for less money! Here’s how:
- Scroll up to the section on “How to Get the James Allen Deals.”
- Follow the easy directions there.
- Feel 100% confident that you bought the best diamond for the money
How to search this site to save up to tens of thousands of dollars at trusted diamond retailers, vs most any Costco, Kay, Jared, or Zales ring you’re considering
Search and save. You could save enough for a new compact car. Or a honeymoon. Or several expensive dinner dates. Or that guitar you’ve been wanting.
Read this very short note on how easy it is.
