IGI vs GIA

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Bottom Line Recommendation

Stick with GIA certified diamonds at Blue Nile or James Allen.

IGI bills itself as a top-of-the-line laboratory, but in our opinion sadly that is not the case. While they may not be as terrible as some of the others, we feel that their grading is definitely more lax and less consistent than the standard bearers in the industry.

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.

We recommend only buying a GIA or AGS certified diamond. Only purchase from reputable vendors that sell diamonds certified by these labs (such as Blue Nile & Brian Gavin Diamonds. James Allen does sell IGI certified diamonds as well, but we never recommend those.) The point of buying a diamond with an independent certificate is to get peace of mind that the diamond is the quality they claim. We feel that an IGI certificate does not deliver that.

IGI Diamond Certification

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

They were 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 their prices are much better than GIA’s.

1) Putting IGI to the Test

We decided to put IGI to the test, given all the conflicting reports about their reliability. We purchased five IGI certified diamonds and sent them to the gold standard of laboratories: GIA.

The results were predictable and unfortunate.

IGI inflated the qualities in eight of the ten possible grades (color and clarity on each diamond). Here are the results:

Diamond IGI Grade GIA Grade
1.04 ct K, SI2 K, I1
1.02 ct I, SI2 J, I1
1.15 ct K, SI2 L, SI2
1.02 ct I, SI2 J, I1
1.00 ct J, SI2 K, I1

*Click on the carat weight for a video of each diamond. Click on the color/clarity grades for respective certificates.

In our opinion, IGI simply does not function at the standards that reputable diamond laboratories hold themselves accountable to. Now we will explain why this matters to you, the consumer.

2) Why Should You (the Consumer) Care About This?

The reason why you must buy a diamond with legitimate certification is to give you peace of mind that the diamond you are getting is the quality the seller is claiming it to be. This allows you to compare the diamond to similar diamonds and make sure you are getting a fair deal.

The problem is that we believe IGI doesn’t deliver on that. In fact, we feel that you are likely getting a subpar deal if someone is selling you an IGI certified diamond. Take a look at these two searches of SI2 and I1 diamonds for comparison:

James Allen Search of SI2 one caraters.

James Allen Search of I1 one caraters.

A typical one carat SI2 diamond will end up costing you around $4,000. A typical one carat I1 (with all the other specs being equal), will cost about $3,000.

So here comes a jeweler who sells IGI certified diamonds.

You see an I SI2 diamond for $3,500, so you think “Wow, I’m saving about 20%!” In reality though, we feel the jeweler is deceiving you and you are overpaying about 20% by using the certificate that inflates the quality claims (based on our and other’s observations).

This is the oldest trick in the book, and it is used by companies to increase their margins while tricking uneducated consumers with less strict certificates.

3) How Diamond Companies Play the Game

I understand, and sympathize, with people in the diamond industry who have seen the competition grow fiercer and the margins grow slimmer every day. Unfortunately, too many of them have decided to go the route of manipulation and trickery instead of coming up with an alternative way to increase their margins (by providing a unique experiences or special products).

You might think “this is just your opinion, others can have a different one” or “you are cherry picking diamonds for a certain result” but that is simply not true. Diamond companies can, and do, cherry pick the results to use the looser certificates with the maximum grade inflation.

Here is another “trick” they use.

In our experience, some IGI laboratories are weaker than others. Many jewelers in America will say something like “oh, those articles are talking about IGI in Botswana or Mumbai or Antwerp. The IGI lab in NY is much stricter.”

And in a way that is true. Unfortunately, those same jewelers can play a simple trick. What you can do is take a diamond that has an IGI Mumbai (or Botswana, or wherever) certificate, and send it to IGI NY with the certificate from Mumbai.

Then the seemingly stricter IGI lab in NY will give you a certificate and “honor” the grades from their sister laboratory.

In fact, we tested this rumor by sending these same five diamonds to IGI in New York. Three of the diamonds did not have a laser inscription from the IGI labs in Mumbai. Two of them did have laser inscriptions from IGI Antwerp.

We sent the three without inscriptions as “new diamonds” and sent the two that had inscriptions with the certificates from IGI Antwerp. Predictably, IGI New York downgraded the three “new diamonds” from their previous grades from IGI Mumbai, but matched the very generous grades from IGI Antwerp on the other two stones.

What does that tell you about their credibility? What does that say about a jeweler who uses IGI?

Unless this was some miraculous coincidence, IGI New York clearly honored the looser IGI Antwerp’s grades. In what way does doing this help the consumer or their credibility as an independent laboratory?

Legitimate laboratories do not let anything influence their grading (GIA ignores any markings you put on the packaging other than your own SKU number and weight, certainly wouldn’t let you tell them the grades of another GIA laboratory in hopes of influencing their decision).

Even though the industry knows about this trick, we were still surprised it worked so easily, so we decided to test IGI again – this time with a more precise methodology.

This time, we took 4 diamonds already certified by IGI New York and we sent them to IGI Antwerp for certification as uncertified new diamonds. After getting the results, we sent these diamonds back to IGI New York with the Antwerp certificates attached (with the intention to influence the new grades). IGI New York was not made aware of the original IGI New York certificates that we had made.

Below are the results of our experiment:

Diamond IGI NY 1st Time IGI Antwerp IGI NY 2nd Time
0.37ct I, SI2 G, SI1 H, SI2
0.37ct I, SI2 F, SI1 G, SI2
0.33ct G, SI2 F, SI1 F, SI2
0.30ct H, SI2 G, SI1 G, SI1

On the one hand, it’s refreshing to see that IGI New York didn’t stoop so low as to match the ridiculously upgraded grades from Antwerp. On the other hand, they were clearly influenced by the accompanying Antwerp certs. Each stone received at least one upgrade.

4) Reviewer’s First-Hand Experience

I know this particularly well, as throughout my professional career, we (myself and Ira, the founder of this site) 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.” This is our opinion based on years of experience.

5) And if You’re Still Not Convinced

On Nov 3rd, 2016, I performed a search on Rapnet (the world’s largest online market for wholesale diamonds – think the NYSE for diamonds) using their TradeScreen™ tool. This tool allows you to get a snapshot of average market asking prices for specific parameters.

I limited my search to 1 carat “triple excellent” round diamonds with no fluorescence. One search I did using only GIA certified diamonds and the other search I limited to IGI certified diamonds.

See the results below:

Grid of GIA Certified Rap Discounts

Grid of GIA Certified Rap Discounts (Click to Enlarge)

igi-price-grid

Grid of IGI Certified Rap Discounts (Click to Enlarge)

Taking the average of the differences of all of these specific color/clarity combinations (weighing each coordinate on the matrix equally), leads to the conclusion that GIA certified diamonds are 18.77% more expensive than IGI certified diamonds on average (at least for 1.00-1.49ct diamonds).

In financial economics, the efficient-market hypothesis states that asset prices fully reflect all available information.

I feel there is only one logical explanation why the wholesale diamond market would price in such an enormous discount in IGI certified diamond prices when compared to GIA certified diamonds: the “market” believes IGI’s grades are inflated when compared to GIA’s.


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