Are Costco diamonds worth it? For this one of my many comparison shopping sprees, I decided to compare a 1.5-carat amazing ring at Costco with a virtually identical ring at James Allen.
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The diamonds of both rings have identical GIA grades
That’s hugely important, of course. The Gemological Institute of America grades the diamonds impartially. You can know what you’re getting.
The settings (actual rings) are also virtually identical Platinum settings
Each ring has a 4-prong Platinum setting that have very similar designs. To my view, the setting of the James Allen ring looks a little more elegant. But let’s call them even. That kind of judgment is always in the eye of the beholder. What’s inarguable is that each is a 4-prong ring of pretty much the same design.
Which store’s deal is better, Costco or James Allen?
Let’s find out. I think the answer may surprise some people.
First, remember that these products are unique. Here’s why that’s important in any comparison.
Long ago when I was new to shopping for diamond engagement rings, I assumed, without really thinking about it, that they were like other products: I assumed there was a certain stock of them at any product page.
But with the best quality diamond engagement rings, there is only one. The diamond has a unique identifier, usually from the GIA. It has a detailed diamond grading report. There’s just one.
That’s the case with these two offerings. The one from Costco. And the one that I’ll build from James Allen.
Here’s why that’s important
If and when you click on the links to these specific products, they may or may not be still available. At Costco, someone may have bought it. At James Allen, someone may have bought the diamond I’ll show you.
So, I’ll use screen shots liberally.
You can use what you learn by watching me
You can learn what you use watching me comparison shop in order to find the best deal for you, when you’re shopping for a diamond engagement ring.
It’s unlikely you’re here looking at exactly this Costco diamond ring. Or this exact James Allen diamond. Heh, in fact it’s almost impossible that that’s the case.
What you are here doing is learning whether Costco diamonds are a good deal, or whether you might find better deals elsewhere with just a little bit of (enjoyable) looking around.
With every one of these comparison articles, you’re learning how to find a great diamond, by shadowing me, not by going through the course. (Although that’s also useful.) Not by trying to absorb pages and pages of some diamond site’s info, as if you’re in a graduate seminar for diamond shopping.
Learning by doing, by shadowing a highly experienced personal shopper for diamonds, is one of the best ways to learn how to find a great diamond for a price you love.
And that’s what you get a chance to do when watching me in these comparison shopping blog posts.
Ok, enough! Let’s look at the diamond ring offer from Costco. Then we’ll compare to one at James Allen.
Costco diamond engagement ring offer: $15,999.99

This is a unique product. If no one has yet purchased it, you can see it live here as item number 1408888 at Costco. (Otherwise it’ll be gone.)
James Allen diamond engagement ring offer: $11,300

How to easily build this ring yourself right now at James Allen
Here’s the setting at James Allen. (It’s $900 at the time of this writing, but sometimes they go on sale. So it may be even a couple hundred bucks less.)
Here are my search settings for the diamond. (The exact one pictured above will likely be gone by the time you read this. But my search filter settings will show you several that are very similar, with the same GIA grades.)
First, start at the diamonds section. Go there now.
Next, set your sliders to what you see in this image:

As you can see:
- The diamonds in these rings have the same specifications from the GIA.
- The setting (ring itself) design is essentially the same. Platinum 4-prong.
- At Costco you’d need to be a member. Not an extra expense if you already are a member.
- At Costco, you’re on your own for resizing. (James Allen will resize it for FREE for a year.)
- At James Allen, you can minutely examine the exact diamond you choose, with their 3D imaging. (No such technology for looking at your diamond exists at Costco.)
- The James Allen offer is $4,700 less.
Um wait, what? Yes. I’m putting that in a heading:
The James Allen offer is $4,700 less expensive
Same quality diamond, as graded by the GIA.
Same basic setting.
Better customer service at James Allen. Better technology for looking at your diamond.
This specific Costco diamond ring is not worth it, in my opinion.
I’d prefer to have the same quality, less cost, and better service, from James Allen.
What do you think?
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.