IGI reliability for Lab Diamonds

[Runner9037]

I've read that IGI is lax in its grading vs GIA for mined diamonds. Does this hold true for lab diamonds? I've noticed that most lab diamonds are IGI cert. and was wondering if I need to adjust my search criteria. I don't want to purchase with an IGI "H" or "I" diamond if it is a GIA "J" or VS1/VS2 that isn't eye clean.

Thanks!

 

[ChristineRose]

This is an unfortunate reality of lab diamonds. Diamond Foundry grades their own stones because of this but they are obviously not independent. IGI is not horrible the way EGL is horrible. I call them the McDonalds of grading. Fast and cheap, low quality, not as consistent as they could be, but basically honest.

I would recommend looking for GemCal. GemCal uses less subjective techniques (machines) to grade stones and is highly reliable. The main problem with GemCal is that their grading is not really comparable with GIA--they look at different things. That and there being only a handful of GemCal stones out of a handful of lab diamonds.

Tools like the HCA and reflector images are also strongly recommended, but you may have a hard time finding a dealer at all, let alone a dealer who will help you with reflector images. You can also use the AGS and GIA cut estimator tools, and avoid the most common reason they give the wrong results--a very thick or very thin girdle.

Sart with an appraiser you can trust. You can ask on the RockyTalky board for help with appraisers in your area. Then pick a promising stone with a good return period. Line up the appraiser in advance, so they can look at your stone the moment you get your hands on it.

Another strategy is to talk to Good Old Gold. They carry a very few lab diamonds, but can help you find a top quality stone and will give you an honest GIA-like grading. You'll pay extra for the service, but that's true of all their diamonds, and lab stones have a much higher hassle factor anyhow.

The truth is that most people prioritize carat weight and buy a mediocre mined stone, and most people who want a lab stone prioritize the lab part, not the cut part. But it can be done.

 

[Skhii]

I've read that IGI is lax in its grading vs GIA for mined diamonds. Does this hold true for lab diamonds? I've noticed that most lab diamonds are IGI cert. and was wondering if I need to adjust my search criteria. I don't want to purchase with an IGI "H" or "I" diamond if it is a GIA "J" or VS1/VS2 that isn't eye clean.

Thanks!

Searching Pricescope will turn up plenty of threads discussing IGI. The vast majority of consumers on PS will strongly advise against IGI because that's what they have been advised from other consumers here. However, according to PS trade members, IGI's bad reputation in the USA have stemmed from their inflated appraisals, as opposed to their grading reports. Some trade members (e.g., John Pollard) have said that IGI labs (i.e., Antwerp, Hong Kong, Mumbai) are well respected in Europe and Asia and are on par with GIA and AGS. IGI NY reports (not appraisals) are okay. There was also a study done comparing various labs: http://www.diamonds.net/News/NewsItem.aspx?ArticleID=43417

If you are purchasing a lab diamond, you likely won't find one with a GIA report because GIA will only give it a color and clarity range (e.g., colorless and VS instead of F VS2). You are better off sending it to a respected independent appraiser with the same GIA lighting equipment and a set of master diamonds. If you do use an appraiser, make sure they can provide light reflector images (especially ASET images for fancy shapes) as well. There are IGI reports for modern round brilliant (MRB) diamonds that have ASET images.

You should be able to find quite a few lab diamond dealers online. Some of them do provide ASET images even if they do not advertise it; you just need to ask! This is one vendor I found online that does: http://growndiamondcorp.com/Home/OurMission. Numined, GOG, and others do as well. You can also purchase your own handheld ASET.

I found some man-made diamonds with IGI reports that have ASET and H&A images included:
A) https://www.brilliantearth.com/lab-diamonds-search/view_detail/3789325 HCA: 0.8 TIC
B) https://www.brilliantearth.com/lab-diamonds-search/view_detail/3789322 HCA: 2.0
You can see Brilliant Earth's definition of super ideal MRBs are not the same as most PSers' definition of super ideal MRBs, but they still perform well. If you really want a super ideal man-made diamond, you'll definitely need to search for it, or request it to be custom cut.

Runner9037, please share your journey with us if you decide to get a stone!

I would recommend looking for GemCal.

What do you like about GCAL reports, ChristineRose?

 

[ChristineRose]

Hi Skhii,

GCAL will fully grade lab stones. They are a reliable lab--in fact they guarantee no difference in the 4Cs if regraded! They can do this because the grading is done by machines computers and is not subjective.

The downside is that their grades don't line up to GIA as well as other good labs like AGS. We don't know how they define clarity for example, because we don't know how their machines score. And their cut grading is completely different from GIA, which is different from AGS as well.