IGI, GiA, AGL-gem labs

[smitcompton]

Hi,

Through the years I have read discussions on these 3 labs comparing them to each other. When assessing a diamond for cut, it appears that the cost of the diamond is in relation to the lab used to grade the stone. IGI graded stones all seem to cost much less than those graded by the two other labs mentioned even if they are graded IDEAL cut. Are we saying that a stone is no good if graded by IGI. Who sends their stones to IGI. Who cuts those stones that sell for much less. Now GIA has ex, ex,ex as grades, but they round off numbers so we may not get a excellent cut diamond anyway. AGL grades diamonds as ideal and are considered the best Lab.

Years ago a jeweler would say something like, "Oh this stone has a very good make. Nice make on the stone, referring to cut.. Did IGI cut stones in the past. How could a Lab never cut a well cut diamond. It seems to me that on this board they are all crap. For what ever reason I don't want an ACA stone. Ideally I would take an expert selection stone, but I just want to find a good cut diamond for a lot less money from IGI. IIs this impossible? Somehow I am having difficulty believing this. And now we must trust IGI with assessing lab cut stones and raise up their value. IGI can cut lab stones to ideal but not earth mined diamonds. Is this true?

Can I put a stones numbers in the HCA if I don't have the cert number. These are from James Allen. No cert numbers.

Annette

Looking for IGI diamonds with good or very good make.

 

[lovedogs]

Why IGI in particular? Gia is much more reliable in terms of color and clarity.

You don't need report number to enter into the hca. Just the angle info.

What are your desired specs?

 

[Karl_K]

I dont have time to tackle everything right now.
I will start and others can pick it up.
Before LGD IGI got lumped into the bunch of labs called not GIA in the USA.
Since they became the standard for LGD a lot of people have taken another look at them and realized they are not so bad.
At the same time they have been making great strides in improving there processes and offerings.

The labs do not cut stones, they grade stones sent to them.

It sounds like you meant AGSL which was absorbed by GIA and no longer exists. The supplier can get an add on report to a GIA report listing the AGS cut grade for an additional fee.

IGI just launched a new cut grade system for well cut rounds.
As a disclosure I am one of the researchers that worked on the project.

IGI is much bigger and more respected outside the US market in the mined good markets.
A mined stone with an IGI report is often sent to GIA for the US market and sold at a higher price to cover it.

 

[smitcompton]

Hi,

The IGI stones are much, much cheaper. One that I posted has a cert from Antwerp, a diamond center. Its marked IDEAL Its hard for me to understand how Antwerp IGI doesnt cut a diamond, at least a good, very good cut.
Here is what I saw. A K Vsi 101 ctw is 1750 on James Allen-Antwerp stone. IGI A K Vsi either the 112 or 101 tcw is just under 10000 at White Flash. It is an ACA. I'm not interested in that

The second stone is a J 112 vvs2 and is 2170. A perfect diamond is not what I expect.

Lovedogs, don't look for me. I need to understand more dynamics.

Annette

 

[smitcompton]

Hi,

I am happy to report that I purchased my first IGI diamond. The HCA gave its over=whelming support of this diamond, and I decided to grab it. It sparkles like crazy, shows no inclusions and while it is a K, I'm fine with that stone. I won't receive it for a least a week and the gemologist will look at it.

I wish to continue this discussion as well. But right now I'm going to make some tea.

Annette

 

[kenny]

Reading here over 20 years results in me having the following impressions about gem labs and the market for diamonds they have graded:

For color and clarity (which I'm going to call CC) grades, GIA & AGS are the most reputable and consistent, the gold standard if you will.
Other American labs have a different business plan.
While they'd get caught if their reports inflated the carat weight.
They get away with inflating the CC grades.

They know that giving inflated (higher) CC grades will result in the unwashed masses of diamond shoppers (who don't do their research/homework) think a G VS1 from a lesser lab is the same (and fair-game for price comparison) as a G VS1 graded by GIA/AGS.
They assume CC grades are as objective and trustworthy as carat weight.
They're not, they should be, but they're not.

They have found a clever way to make higher profits, but IMO it is dishonest, if not fraudulent.
They get away with it buy saying CC are just opinions.

Example: a diamond that GIA/AGS grades G SI1 is more likely than not to get better grades, such as F VS2 or E VS1, from the less-reputable labs.

So, calling GIA/AGS stones "more expensive" shows a lack of understanding of how it is NOT comparing apples to apples.
Instead of callingGIA/AGS-graded stones diamonds more expensive, I'd call them diamonds with with CC grades that are not lies.

But generalization are just that, generalizations.
Every generalization has exceptions.
If they didn't, they'd be called rules, not generalizations.
Importantly, those exceptions do not make the generalizations not true; they are still true, just generally true.
That's why generalizing is okay.

Me, I work hard for my money.
I want to be sure as possible that I'm getting what I'm paying for.
That's why GIA/AGS are the only labs I trust enough to support with my dollars.

But then I don't gamble at Vegas, or play the lottery either.
As always, people vary ... YMMV ... but it's good to be informed of the above before selecting the gem lab that gets your dollars.

 

[kenny]

ETA
When it comes to Fancy Colored Diamonds that are fully natural (IOW earth-mined and not color-treated) GIA is the only American gem lab I trust enough to tempt my wallet.

But when it comes to cut grading D-Z white diamonds for the best overall light performance, I visualize a target.





While not a perfect analogy, I think of GIA's top cut grade, Excellent, as the larger gray circle, but AGS's top cut grade, AGS 0, as the smaller red circle.
Gray is better, but red is best.
A round D-Z also has to have a good HCA score.

I work too hard for my money to settle for just better.

As always, YMMV when it comes to your purchasing preference.
But, facts are facts and it's always better to be better-informed.

 

[smitcompton]

Hi,

First, I just want to say that i do understand that IGI doesn't cut the stones it evaluates. That was unclear in my post. My point is that those graded stones are much cheaper than those from other labs. So, in a diamond center such as Antwerp, cutters are sending their poorly cut stones to IGI. My comments are on cut. Kenny has brought up C?C. My concern was cut, which we have been told is the most important component of the diamond. If the color is a few grades off and the clarity is off, that is more easily discernable. aspect. You see, the lab does not cause the diamond to get higher prices. The opposite is true. Low Prices. So why is this cheating or dishonest? No gain. Diamonds assessed by the other labs cause greater values. Are there no diamonds assessed by IGI that pass muster?

I found 2 diamonds that I put through the HCA. When I purchased the diamond I jokingly said to myself. HCA made me do it. It was quite a surprise for me, considering. It came in 0.9. It said Should sparkle beautifully, but looks small for the weight.
Light Return-- excellent
Fire==excellent
Scintillation--excellent
Tyty posted last week that a 1 ctw should be 6.46 diameter. This diamond is 6.35 All fine with me. Want 2 tcw studs. K is fine VS1- no inclusion on table-side. Asking gemologist to check sparkle and inclusion. The cert is dated April 2024. So Kenny, lets hope Karl is right, they have improved. Yes the diamond was 1,760. At the moment I don't feel cheated at all. I'm planning to look for another one--not just yet.

Annette

I can't help myself---DeBeer is reducing it Lab diamonds by 40%































the beauty in an excellent cut diamond wil

 

[0515vision]

Would love to see your stone when it comes in. Being heavily lab-leaning, I have great faith in IGI and would be happy to help you look for a mate for this stone of yours. There are plenty of great non-ACA IGI diamonds out there.

And I wonder how much of the price difference of IGI stones vs GIA/GCAL stones is based on the vendor? Those vendors know they can hype of a GIA certificate, and they can take advantage of that. A savvy IGI consumer is going to be able to find equally beautiful diamonds.

 

[smitcompton]

Hi,

Oh how nice

Would love to see your stone when it comes in. Being heavily lab-leaning, I have great faith in IGI and would be happy to help you look for a mate for this stone of yours. There are plenty of great non-ACA IGI diamonds out there.

And I wonder how much of the price difference of IGI stones vs GIA/GCAL stones is based on the vendor? Those vendors know they can hype of a GIA certificate, and they can take advantage of that. A savvy IGI consumer is going to be able to find equally beautiful diamonds.

Hi,
How nice to hear you say that. A voice in the wilderness. I d suspect what you say is true. I don't know how all stones sent to IGI must be bad. Well I've got a lot of learning to do, but IGI is on my radar.

Thanks

Annette

 

[smitcompton]

Hi,

I'm flummoxed. I have put three stones with IGI certs into the HCA. Two stones came back 0.9 and 1.0 all ex for Light return, fire and Scintillation The last one was average for size. 1890.00 K VS2. For studs these are great.

These stones are looking good. This cert was 2023.
i AM AMAZED.

aNNETTE

 

[TXwidow]

Hi,

Oh how nice


Hi,
How nice to hear you say that. A voice in the wilderness. I d suspect what you say is true. I don't know how all stones sent to IGI must be bad. Well I've got a lot of learning to do, but IGI is on my radar.

Thanks

Annette

I would not call them 'bad' but if you want the best of the best then you will probably not be happy with IDI graded stones. If for a pendant or earrings you might be happy.

 

[0515vision]

In your other thread, you didn't mention crown angle or pavilion angle. Those, along with depth and table, are some of the staple numbers here on PS. With the crown angle range being 34-35, as you get steeper, you want a shallower pavilion angle (range 40.6-41).

With that knowledge alone, you can sort through some stones and come up with potential contenders. The reason we keep asking for videos is bc we'd like to see the degree of twist or painting&digging, etc. But those other numbers and the HCA will get you started.

 

[kenny]

Smitcompton, I'm glad you are happy with your choice.

Like I ended my post ... "As always, people vary ... YMMV ... but it's good to be informed of the above before selecting the gem lab that gets your dollars."

 

[MissGotRocks]

Hi,

Oh how nice


Hi,
How nice to hear you say that. A voice in the wilderness. I d suspect what you say is true. I don't know how all stones sent to IGI must be bad. Well I've got a lot of learning to do, but IGI is on my radar.

Thanks

Annette

I think the thinking of cutters is that if they think a diamond will qualify as a GIA triple excellent, they would send the diamond to GIA. If they don’t think it will get that grade with GIA, they send it to another lab where it might earn their top mark. AGS was the top tier lab in terms of cut analysis as they didn’t use rounded numbers, but rather used actual crown, pavilion, etc. numbers. GIA is, of course, the most recognized lab around the world. I don’t think that any diamond dealer would consider GIA and IGI on par at this time. Of course, AGS was absorbed by GIA. That is why less stellar cut diamonds are sent to lesser tier labs than GIA - just trying to get the best cut grade they can from whatever lab they choose to use. They won’t pay for GIA cert if they know the diamond won’t get the top grade from them. Hopefully this makes sense and is a bit clearer.

 

[0515vision]

@Rockdiamond @Wink @Texas Leaguer @Rhino , any of you Trade gentlemen able to shed some light on when stones get sent to GIA vs IGI?

@Garry H (Cut Nut) @Serg @Karl_K, any of you gentlemen know?

The premise is that stones of lower quality which won’t get GIA triple Ex are sent to IGI since vendors know they won’t be able to get top dollar on a non-triple Ex GIA stone.

Thanks in advance!

 

[kenny]

I know you didn't ask me, but, IMO it's not about diamond quality "quality".

It's about catering to a different group of buyers.
People vary.

Some are looking for one thing.
Some are looking for another.

IMO that's okay.
As always, there isn;'t one way that everyone must conform to.
GIA/AGS appeals to one group, and they have their reasoning.
Other labs appeal to another group, and they have their reasoning.

 

[Serg]

Hi,

Through the years I have read discussions on these 3 labs comparing them to each other. When assessing a diamond for cut, it appears that the cost of the diamond is in relation to the lab used to grade the stone. IGI graded stones all seem to cost much less than those graded by the two other labs mentioned even if they are graded IDEAL cut. Are we saying that a stone is no good if graded by IGI.

Annette

Looking for IGI diamonds with good or very good make.

Cutters send stones to laboratories where the certification cost is less than the added value created by the certification. The cost of certification usually depends only on the stone's weight, meaning it is an additive addition to the diamond price per carat. The added value from certification acts as a multiplier to the price per carat.

If a cheap diamond is sent to a laboratory with high service costs, the added value from certification will be lower than the cost of certification because the low cost per carat of the diamond does not allow for a significant increase in value from certification. The price multiplier for a diamond after GIA grading is substantially higher than after IGI certification.

Therefore, it is not profitable to send diamonds with low color and flaw characteristics to GIA, and it is not advantageous to send natural stones graded D-E / IF-VSS to IGI, despite the lower certification costs at IGI. Due to the low cost of synthetic stones, their evaluation becomes unprofitable in laboratories, leading laboratories to shift towards a business model where all technical work on evaluating diamond characteristics is done by the diamond manufacturer, and the laboratory charges for the brand and provides some technologies for certification.

 

[smitcompton]

Hi,

I just went to Whiteflashs site to check on K, VSI, Gia certified diamonds. ! ctw. Prices ranged between 2800- to over 5000,00. The spec are similar to the two diamonds that I put through the HCA, costing much less.
There are many people like myself who do not need perfection, but want a well cut stone for a decent price. For me, if what Karl says is true that IGI stones are sent to GIA for stateside consumption that could prove that IGI diamonds may offer a better value or the same value as some GIA stones.

There seems to be a bias here against IGI stones, and it is so much easier to just go to Whiteflash and recommend their stones.

With diamond prices falling and people like Mrs B finding value in a 1.50 well cut pear diamond for 2,600.00, I would think that some people should be looking at IGI, lower cost , and finding good value.

Serg- thank you for explaining the lab world. So far my own experience says IGI is a lab to consider as well as the others.

Annette

 

[Rockdiamond]

Serg gave an excellent synopsis.
My perspective? Things are changing. Rapidly.
If you'd have asked me a few years back what I thought of IGI.....it wouldn't have been pretty.
Now, after having experienced literally thousands of IGI graded stones, my confidence level has risen dramatically.
But the changes haven't (yet) allowed IGI to solidify a place in the natural diamond market.
Serious natural diamond cutters still feel they need GIA.
BUt as I said- things are changing...rapidly

 

[MissGotRocks]

Hi,

I just went to Whiteflashs site to check on K, VSI, Gia certified diamonds. ! ctw. Prices ranged between 2800- to over 5000,00. The spec are similar to the two diamonds that I put through the HCA, costing much less.
There are many people like myself who do not need perfection, but want a well cut stone for a decent price. For me, if what Karl says is true that IGI stones are sent to GIA for stateside consumption that could prove that IGI diamonds may offer a better value or the same value as some GIA stones.

There seems to be a bias here against IGI stones, and it is so much easier to just go to Whiteflash and recommend their stones.

With diamond prices falling and people like Mrs B finding value in a 1.50 well cut pear diamond for 2,600.00, I would think that some people should be looking at IGI, lower cost , and finding good value.

Serg- thank you for explaining the lab world. So far my own experience says IGI is a lab to consider as well as the others.

Annette

There probably is a general bias against IGI stones. As has been stated, they were not always the most reliable. However, I don’t go to Whiteflash to buy or recommend stones because it is easier. I do so because I have had several ACA diamonds and prior to that, had several non ACA diamonds. The difference was night and day. I am particular and want as much info about what I am buying that I can get. I can recommend them because I have had a fair bit of personal experience with them and won’t hesitate to suggest them.

We are all different and have different thresholds for what is acceptable and of course, one of those thresholds is price. I know you have been looking for a while now. I hope that the diamond you have selected checks all the boxes for you and makes you very happy. Only you can determine which characteristics are most important to you. I hope you will share pictures with us when you receive it!!

 

[Texas Leaguer]

@Serg gave an excellent summary of the economics of lab shopping. And I think it is very relevant, especially to smaller stones and those in the commercial grades (and lab diamonds).

Because of the sliding scale of natural diamond pricing based on size and amplified by the higher grades, the cost of the lab report rapidly becomes less of a factor to the overall price of the product. And as the size and quality increases the stakes for the consumer become much higher, encouraging the use of the lab with the best reputation for accuracy globally.

We may feel like other labs such as IGI, HRD, GCAL, GSI do a great job, and in some cases provide more value to consumers. But the fact is GIA is so well known that most consumers today still consider GIA the final arbiter of diamond quality.

 

[0515vision]

Due to the low cost of synthetic stones, their evaluation becomes unprofitable in laboratories, leading laboratories to shift towards a business model where all technical work on evaluating diamond characteristics is done by the diamond manufacturer, and the laboratory charges for the brand and provides some technologies for certification.

Could someone explain this more? Is @Serg saying that lab stones are generally evaluated by the cutter/manufacturer, and then merely sent to certification houses for a stamp of approval?

 

[smitcompton]

Hi,

I thought that GIA is not well known in Europe. This is a US used Lab. Is that right or wrong? I totally concede that many people, especially those that are looking for a larger, more perfect diamond than I am would want the most reliable lab to assess the stone. But, as I said the spec I and some others may be happy with don't need to go to "the best lab". .

I'd like to explain further. I began to think about this as I followed OLD Fossils Journey buying diamonds for his wife.At one point he was concerned that his perfect diamond was 2% off the ideal on light return. This reminded me of when my mother bought a hi fi sound system in the 1950s. MY brother claimed it as his when my parents died. Well, sound improves and improved, and so sound lovers bought many very expensive systems. Then came the news that some of these sounds could not be heard by the human ear, and thus your dog would enjoy the music more fully.

OK-- So when Old Fossil wanted that 2@ more light return I wondered if the eye could in fact discern the difference. I'm not sure, but again, I suspect maybe no. It turned out just to be camera work that distorted the light return. But I wondered if 2@ off was that important. Thats when I decided to lower my parameter and began to look at IGI. I could miss some light return, I think and still have a lovey diamond. Would my eye even discern this.

O515- Thanks for 2 things. You helped me understand, at least aa little, how to read the angles. And your question above needs an answer. Seems it is necessary to put down IGI. Hey they can start sending lab diamonds to GIA.(Just a joke)

Thanks All.
Annette

 

[0515vision]

i’m driving and dictating at the moment, so I’m unable to find the thread I’m thinking of. But I wanted to touch on the idea and perceived value of 2% more light return.

But @0-0-0, didn’t you show us in the lab forum that a branded cut next to a well selected non-branded cut essentially have the same light return? Granted, I think you said that the viewing distance had to be taken into account. But as I recall, your viewing distance was something like the difference between 6 inches from the eye, and 2 feet.

@0-0-0, your meticulous threads are so enlightening and appreciated!

 

[smitcompton]

Hi,

GIA has a lab in London and Bangkok, IGI is all over Europe, Asia, and India. So GIA is mostly for the US market. My brief reading says IGI is a good lab, but GIA is the gold standard. where you can get higher prices for your diamonds, as a seller, if you have a cert from them. Is it any wonder that GIA is promoted as it is.> Very self serving.

I;ll take a rest before I make too many enemies.

Annette

 

[0-0-0]

Could someone explain this more? Is @Serg saying that lab stones are generally evaluated by the cutter/manufacturer, and then merely sent to certification houses for a stamp of approval?

Perhaps referring to this?

Lab-Grown Diamond Brand Lightbox Cuts Prices by 25 to 40%

The move follows a price-drop test run in Q4 and comes with the addition of a “quality assurance card” from GIA for some loose diamonds.

nationaljeweler.com

Also on Friday, Lightbox announced it would now be obtaining batch quality verification for its lab-grown diamonds through the Gemological Institute of America.

Lightbox said GIA will assess a “statistically significant” sample in each production run to ensure they meet the lab’s quality criteria for color, clarity, and cut. A downloadable GIA “quality verification card” then will be available for each diamond in the batch.

A GIA spokesperson told National Jeweler that the batch verification service launched Friday. It is a service GIA is providing for Lightbox only, just as it does pre-owned jewelry authentication for eBay only.

The service will start with the Lightbox’s D-F color white round brilliant-cut loose lab-grown diamonds, though it could expand to the blue and pink lab-grown diamonds in the future.

 

[0-0-0]

i’m driving and dictating at the moment, so I’m unable to find the thread I’m thinking of. But I wanted to touch on the idea and perceived value of 2% more light return.

But @0-0-0, didn’t you show us in the lab forum that a branded cut next to a well selected non-branded cut essentially have the same light return? Granted, I think you said that the viewing distance had to be taken into account. But as I recall, your viewing distance was something like the difference between 6 inches from the eye, and 2 feet.

@0-0-0, your meticulous threads are so enlightening and appreciated!

I think you may be referring to my response to your questions in my comparison between IGI graded H&A rounds and an AGSL graded AGS 0 cut round.

Good questions!

The 1.312 is not a branded cut. It’s one of the AGS graded labs I found and ordered from Ritani. The AGS report includes ASET and H&A images so I was reasonably certain that it is well cut.

The averaged pavilion angle as noted on the reports is the same 40.7 on the 1.312 and the 1.7 pair. Both AGS and IGI round angles to 0.1. I think the crisper patterning in the ASET and the more even looking hearts infer less variance/more precision in the non averaged angles. The crisper patterning matches the patterning of branded H&A cuts that I own.

I consider anything within arms reach (~2 feet) to be ring distance, and anything beyond that to be earring distance. So in my comparison, I find that the marginal improvement in cut precision in H&A rounds is more eye catching in motion than a ~20% increase in face up size at a distance of up to ~2 feet.

I compared them on ears at farther distances by putting them next to each other in the same gem box, holding the box next to my face, and looking in the bathroom mirror (~2-4 feet).

I think advanced imaging can help narrow down options for better cut stones, but at the end of the day I still have to see and compare the actual stones to see if the differences matter in person.

The cut on the 1.7 pair is perfectly acceptable, even for a ring, had I not had the better cut 1.312 as a point of comparison. Others may not find the cut differences to be as apparent and opt for bigger size.

 

[V_sh]

Hi,

Just my opinion

_Light return is a very basic thing to evaluate a Diamond cut

_Some experiments show that considering Main facets angles and table size only is not even close to accurate for grading a Diamond cut (this is what all labs are doing right now)

_If you are looking to grade Color and Clarity we can discuss what labs are good or bad and we may conclude GIA is really good

_If you are looking to grade Cut, none of the current methods that labs use are meeting adequate precision

_Diamond industry spends a VERY small part of its profit on R&D (especially grading R&D) and the foundation and basics of the methods that Labs are using are TOO old to be trusted (at least for me)


In the end, I would ask you to do some experiments, then you will know where my opinions come from


Here I'll give you some specifications of a Diamond that can out-compete 99% of the diamonds in the market right now (considering Brilliance, Fire, Symmetry, and Brightness), Just check which Lab or Vendor would possibly grade this diamond as "Superior" Diamond

If you possibly thinking of disagreeing that this diamond is a well-cut diamond I should say that this diamond is a famous one and it's really superior.





Main Pavilion: 39.98°
Lower girdle: 41.05°
Lower girdle length: 80.5%

Main crown: 39.05°
Star: 25.81°
Star length: 61.7%
Table: 60.95%
Upper girdle: 49°



Just compare the specifications with GIA, AGS, and IGI charts, they didn't even consider such a diamond and not even close to a good diamond they would grade it.


If any Cut Grading system can grade this stone as a well-performance stone then I personally can consider that Grading system.

 

[Garry H (Cut Nut)]

Hi,

Just my opinion

_Light return is a very basic thing to evaluate a Diamond cut

_Some experiments show that considering Main facets angles and table size only is not even close to accurate for grading a Diamond cut (this is what all labs are doing right now)

_If you are looking to grade Color and Clarity we can discuss what labs are good or bad and we may conclude GIA is really good

_If you are looking to grade Cut, none of the current methods that labs use are meeting adequate precision

_Diamond industry spends a VERY small part of its profit on R&D (especially grading R&D) and the foundation and basics of the methods that Labs are using are TOO old to be trusted (at least for me)


In the end, I would ask you to do some experiments, then you will know where my opinions come from


Here I'll give you some specifications of a Diamond that can out-compete 99% of the diamonds in the market right now (considering Brilliance, Fire, Symmetry, and Brightness), Just check which Lab or Vendor would possibly grade this diamond as "Superior" Diamond

If you possibly thinking of disagreeing that this diamond is a well-cut diamond I should say that this diamond is a famous one and it's really superior.





Main Pavilion: 39.98°
Lower girdle: 41.05°
Lower girdle length: 80.5%

Main crown: 39.05°
Star: 25.81°
Star length: 61.7%
Table: 60.95%
Upper girdle: 49°



Just compare the specifications with GIA, AGS, and IGI charts, they didn't even consider such a diamond and not even close to a good diamond they would grade it.


If any Cut Grading system can grade this stone as a well-performance stone then I personally can consider that Grading system.

That ideal-scope image is not of the proportions listed