Costco Quality Diamond


May 15, 2009
There's really not enough information in the ad to tell you what kind of quality diamond you will receive. The ad doesn't list a specific GIA report number. You might receive a well cut diamond or you might get a dud. $15k is a lot of money to spend on something when you don't know specifically what you are getting. If you decide to go with this, check on their return policy and make sure you can live with the terms.

(you could find a 1.5 ct from a trusted PS jeweler for less $$$$ and know what you are getting)


Jul 27, 2011
Hi George,

Any reason why you are looking at Costco?
As an FYI, if you resize the ring, you cannot return it.


May 3, 2001
There is no specific diamond certificate with this ring because they have a bunch of them and will pick one when you contact them. Unless things have changed since the last time I took a good look at one of their rings that was brought in to me for inspection after purchase.

From Costco I have seen absolute garbage and very nice diamonds. I suspect that they are nicer now than they used to be, but if you are an educated buyer you will want to personally inspect your diamond and look at the reports prior to putting it on your credit card.

Given that you do not have access to a given report we can not offer you much advice on this diamond.


P.S. Read the small print. I do not know if Costco still has the plus or minus 10% thing on their small print. (They are hoping to sell hundreds, or thousands of these, so they list the "approximate" weight and give you the high and the low of it. Or at least they did at one time.) if so, buying a 1.5 ct could get you as low as a 1.35 or as high as a 1.65. Given that there is a substantial discount from a 1.50 ct at 1.49 cts, that can be an important thing to establish prior to buying the ring.


Jul 21, 2004
I’m pretty loyal to Costco. I shop there a lot. That said, I’m not convinced they’re a great place for jewelry, especially diamonds. Here’s the problem:

Center diamond 1.50/I/VS2/GIA. No info on cut so let’s assume VG and ‘none’ on fluro. Is that what you want? Maybe, but there are a ton of other choices and there’s nothing about that shines as being the best. That’s not even especially popular. Let’s assume it is and move on. There are 482 stones in the database here that meet that spec and the discounty price is about $8000. (use the search utility at the top of the page. I used 1.50-1.55/I/VS2/GIA only). Rock bottom is $6,568.

Side stones. 6= 1.50cts total weight. 0.25cts each. GIA isn’t involved here, nor would I expect them to be, but I/VS2/quarters are going to run you something like $1500/ct. from the usual dealers around here. $2,250 for the side stones.

Metal. Even less info here but that’s a reasonably mainstream sort of design. Pretty much any jeweler can put together a mounting like that with, say, 10g of platinum. $1500 will cover your metal costs just fine for a non-custom mounting.

Labor to set and size it is another that can be all over the map. $500 should do you just fine.

You’ve still got nearly $3000 in your pocket! You can use it to upgrade something or just keep it. More importantly, if what you want is a little different from the above, if you use a real jeweler they’ll have no problem accommodating you. Only want 2 stones on each side? No problemo, and the price will go down too. What a halo added? No problem. Add a thousand or so and it's yours. Want to upgrade or downgrade the cutting, the color, or something else? Want it a little more petite? Want a size that’s different from the 3 they offer? No problem, you can have any size you want and picking a different size won't void your return policy (at Costco it will).


Feb 8, 2014
When I first got engaged, and before I knew anything about diamonds, THAT is the exact ring we bought. It went back in less than 24 hours. When we opened the box, and everywhere I wore it for the next twenty hours, that center stone was grey and dead looking. Researching what made what should have been a beautiful GIA XXX stone so drab and lifeless, is what led me here.

Do you know what I discovered in my many months of research? Cut is king. As is commonly known, GIA is a very lax grading system - many different kinds of stone can fall into that XXX category and still be absolute dog rockets. That's why I like AGS, they're more stringent about what they consider a triple 000. I went to a lot of places, talked to a lot of people and looked at a LOT of stones. I ended up buying a Crafted by Infinity from High Performance Diamonds and couldn't even begin to describe the difference in brilliance between the two stones. The CBI looks like it is lit from within - it takes ANY ambient light and glitters ferociously. Not so with the inferior Costco cut stone. That stone had no life, light return or scintillation. It was just grey and washed out.

I imagine there are less finicky people out there that would only look at the size of the center stone and be happy - but I could not, in good faith, blow $15K+ on that crappy ring. For just a little more, HPD got me a 1.3 center, custom made a platinum set with 6 x .2 in the ER and 7 x .25 in the WB, and I'll tell you, I get people come from across a room to see my rings, they are so dazzling. I get comments very day. Their return and exchange policies, added to their stellar customer service, made the decision a no brainer and well worth the few dollars extra I paid for the peace of mind of having a VERY high quality stone.

Had you said you were buying some earrings from Costco and the price was right, I'd say it's not as big of a problem - not too many people can see their own earrings when they're wearing them. But women look at their rings A LOT. Eventually, she will see it next to a quality diamond and realize she doesn't have one.

Just my $.02 and worth exactly what you paid for it.
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