If you’re out there looking for the best diamond for your money, then please contact us and let us know your budget and what you’re looking for. We’ll sift through thousands of diamonds online and send you suggested stones to choose from that fit your needs the best.

Bottom Line Recommendation

If you will be buying an SI1 or SI2 clarity diamond (as we generally suggest), we recommend only buying a GIA or AGS certified diamond. Only purchase from reputable vendors that sell diamonds certified by these labs (such as James Allen & Brian Gavin Diamonds).

Even the largest jewelry insurance underwriter writes: “The most reliable diamond certificates (also called diamond reports) come from the Gemological Institute of America (GIA) and the American Gem Society (AGS). These are the most respected labs, known for their accuracy and professionalism. These reports are not appraisals and do not carry valuations. Certificates from any other sources are often questionable and should not be relied upon by insurers.”

Likewise, Dateline raised serious questions about IGI’s integrity in 2005 as pertains to their appraisal values.

IGI Diamond Certification

The IGI started out as the blue color workhorse of the diamond business.

They were, and still are, the most popular gem lab for the major jewelry chains in the US and Canada (Kay, Zales, etc.)

They are like a factory. They work fast, and they work cheap.

IGI Competing Against Other Laboratories

Lately, though, they have been trying to position themselves as a legitimate contender against the other labs and not just as a certificate factory for the major chains.

IGI Abroad

While they haven’t succeeded so much in America, they have actually gained quite impressive market share in Europe and the Middle East.  I used to travel to sell diamonds in Dubai, and the two major certificates sold in that market are HRD and IGI.

IGI’s SI2 Sweet Spot 

The bottom line with IGI in comparison to GIA is that I believe they are, in my professional opinion informed by years of experience working for one of the largest diamond manufacturers in the world, consistently looser in the lower end of the color and clarity spectrum – exactly the grades we tell our readers to focus on.

On the other hand, Rapaport actually did an experiment pitting the major labs against one another. In this experiment, IGI only exhibited a very slightly looser grading than GIA. The problem with the experiment, though, was that it focused on either higher clarity grades. There wasn’t a single GIA SI2 in the bunch.

From my experience at Leo Schachter, I believe the problem is specifically in the “SI3” range, where they generally upgrade to an SI2.  Diamonds used for “SI2” programs at the major chains would almost never pass a GIA “SI2.”

Have a look at these IGI SI2s that would almost certainly receive an I1 grade from GIA:

1.03 H SI2, 1.12 H SI2, 1.09 H SI2, 1.31 I SI2, 1.00 H SI2, 1.25 H SI2

Furthermore, a quick glance at wholesale diamond listings on the trade-only website Rapnet, shows that there’s a built-in discount for IGI certified diamonds.  Presumably, the market agrees that there is a certain average upgrade of IGI certified stones over and above GIA certified stones.

On a search performed on October 22nd, 2015 for all well-cut 1 carat round diamonds with a color of I or J and a clarity of SI2, the average discount from the Rap Price for the IGI certified stones (20 stones) was -40.25% whereas the average discount for the GIA certified stones (57 stones) was -34.56%.

The corresponding average prices for the diamonds were almost 10% lower for IGI certified diamonds.

Reviewer’s First-Hand Experience

I know this particularly well, as throughout my professional career, I must have personally selected thousands of diamonds to be sold as IGI SI2s at the major jewelry store chains in the US and UK.

These programs (usually the middle-ground price point offering great value as it’s the cheapest of the eye-clean grades) all have a minimum of SI2 clarity.

For these programs, we would always strive to find diamonds that were in that “SI3” sweet spot — diamonds that would not receive an “SI2” from GIA, but were too nice to sell as an “I1.”

Still afraid of getting ripped off?

Before you buy a diamond, get personal buying advice from industry veterans. We'll help you get the best diamond for the money.

Leave a Comment


  1. daniel     Reply

    Why aren’t you fans of blu enile?

  2. Justin     Reply

    I’ve been researching around for diamonds. I came across Zamir Diamonds having an IGL (International Gemological Laboratories). The prices are surprisingly low, which is why I’m on here. I’m checking the legitimacy of both. Have you heard of either of these and do you think I should trust them with my business?

    Thank you!

    • Mike     Reply

      Hi Justin,

      I don’t know anything about Zamir, but IGL is not an acceptable certificate. Stick with a legitimate certificate (GIA/AGS only).

  3. Nan     Reply

    Hi Mike:
    I always believe that Costco has best price and good quality. I got this ring with IGI cert paid $6400 plus tax from Costco:
    1.01 carat, I, VS2, excellent cut, very good pol/sym, 62.2% TD…
    Now I see the Blue Nile has so many selections with GIA cert. I may get the similar one with only around $5200 and its GIA cert!

    Is Costco the good place to buy a diamond ring? If not, in your opinion which one is good place to go, Blue Nile, Kay or Zales…?

    Thanks a lot!


    • Mike     Reply

      Costco used to be ok, but they have dropped considerably in value the last year or so. They no longer certify rings (I believe under 1.20cts) and they rely far more on IGI than GIA (where they used to usually have GIA certificates over a carat). While we are not fans of Blue Nile, there are plenty of other options to getting better value. It depends what you are looking for.

      If you want specific advice on finding a diamond, feel free to contact us directly. We generally answer a lot faster and write far more detailed responses. We reserve the comments for general statements that can be helpful to everyone.

Click for Diamond Purchase Advice 100% Free

Ask your diamond purchase question here


DISCLAIMER: We don't use your email for marketing. Period.