Find your diamond
Find your jewelry
shape
carat
color
clarity

EGL vs. GIA with Data Comparison

AnneinGA

AnneinGA

Shiny_Rock
Joined
Aug 6, 2010
Messages
403
I'm an accountant, so data appeals to me. And one thing in this giant undertaking of a diamond learning process is the ongoing debate between EGL and GIA. So I thought I'd pull a relative sample and see what I could find out.

I pulled 2.28 RB from F-I color and VS2-SI1 Clarity. I then sorted by measurement, then price (you can't sort by measurement on PS). So I determined that many online vendors sell the same diamond, often differing in price by just a couple of dollars. The same diamonds are sorted together and shown in the same color shade; GIA's are one of two blue shades, and EGL one of two orange shades.

I also pulled all the certificates of all the diamonds I could, and ran the HCA score, which I added in the first column. I used Angles (not percentages) on all the HCA as EGLUSA provides the angles, and I could not pull any EGLInt'l certificates.

The items set off in the middle with two white bars over and above were the two closes diamonds I could compare for measurement and EGL vs. GIA. You can compare their assigned colors by the agency and then the prices.

There is a lot of data to look at, but I would love feedback regarding your interpretation of the data.
 
Here is the data (I HOPE)

diamonds.jpg
 
I m not sure what you are trying to compare. The big concern that many of us here have, is that EGL is more lenient with their grading. For example, take two of the G, SI1's. One graded by GIA is $8654 per carat. Graded by EGL they run ~$6500 per carat. The problem is, with the more lenient grading from EGL, that G SI1 graded by EGL could potentially be a I I1 if it were graded at GIA standards...
 
Anne_

Good work, this confirms what many of us have been saying for a while. The wholesale (and thus retail market) discounts EGL grading as they know it to be soft. Subtract a couple of grades in color and/or clarity and you will match up with GIA/AGS stones prices on average. Market pricing isn't perfect in diamonds but matching the price of an EGL stone with the same priced GIA stone can tell you roughly what color/clarity grade would have been had it been sent to GIA.
 
If you want to compare stones sight unseen using only lab data, the FIRST criteria is the choice of lab, not clarity/color/weight. Compare GIA's against other similar GIA's, EGL-USA's against other EGL-USA, EGL-International against other EGLI's etc. There simply is not a conversion from the way one lab grades to the way the others grade. Even within a particular lab there are a fair amount of issues to consider and each grade represents a range of possibilities but you can come a lot closer to comparing apples to apples if you do it this way.

I'm an accountant too and I understand the attraction of having hard cold numbers that you can go by but this is NOT what you're doing. It's more like you're shopping for a car, you're looking for a 'creampuff' and are aiming for the cheapest one that some dealer is willing to call that.
 
by denverappraiser » 05 Sep 2010 15:15
If you want to compare stones sight unseen using only lab data, the FIRST criteria is the choice of lab, not clarity/color/weight. Compare GIA's against other similar GIA's, EGL-USA's against other EGL-USA, EGL-International against other EGLI's etc. There simply is not a conversion from the way one lab grades to the way the others grade. Even within a particular lab there are a fair amount of issues to consider and each grade represents a range of possibilities but you can come a lot closer to comparing apples to apples if you do it this way.

I'm an accountant too and I understand the attraction of having hard cold numbers that you can go by but this is NOT what you're doing. It's more like you're shopping for a car, you're looking for a 'creampuff' and are aiming for the cheapest one that some dealer is willing to call that.
If you want to compare stones sight unseen using only lab data, the FIRST criteria is the choice of lab, not clarity/color/weight. Compare GIA's against other similar GIA's, EGL-USA's against other EGL-USA, EGL-International against other EGLI's etc. There simply is not a conversion from the way one lab grades to the way the others grade. Even within a particular lab there are a fair amount of issues to consider and each grade represents a range of possibilities but you can come a lot closer to comparing apples to apples if you do it this way.

I'm an accountant too and I understand the attraction of having hard cold numbers that you can go by but this is NOT what you're doing. It's more like you're shopping for a car, you're looking for a 'creampuff' and are aiming for the cheapest one that some dealer is willing to call that.
Click to expand...

On the contrary, I am not looking for the cheapest anything. I was attempting to put data to either support or disprove the fact that most everyone says if you went down 1.5-2 steps on color and clarity from an EGL to a GIA stone, that you would in fact pay more for the EGL "up" graded stone.

However, there is some subjectivity to all grading, and I for one would not buy a stone sight unseen for any reason. On a recent stone-looking trip I was able to look at a 2 ct. GIA "I" vs. a 2 ct. EGL "I" and the EGL stone was MUCH more tinted than the GIA. However, I saw two other GIA/EGL I stones where the color was much closer.

I paid an Atlanta appraiser for about 45 minutes of his time last week to pick his brain about diamond buying, what he used to buy, and things to watch out for. He suggested GIA and AGS because they are WAYYYYY more consistent in their grading, and, to paraphrase him, EGL is a crapshoot. I completely agree.

But I still say that you buy and wear a stone and not a certificate, and I endeavour to find the most beautifully cut, whitest eye-clean stone for the best price.
 
Hi Anne,
I totally understand what you are trying to do and I'm also in finace/accounting ::) , and when I hunt for loose stones, I seriously do the same thing! and I agonize for such a long time (or short amount of time, but intense :rolleyes: ), back and forth. In the end I go with what I feel/trust and have experience more which is to go with GIA/AGS graded stones in general, consistency is key to me when I buy site unseen. Although, it would be very different if I had the stones in front of me to compare, and at that point I don't care who it was graded by as long as the specs and my observation in person concludes what I am buying.
 
Here's another aspect to this.
Say you're looking at an EGL graded J color 1.00ct fancy shape.
It's probably going to be less than $2000- sometimes a lot less.
In that case who cares if it's an L or an M or Q-R color -I've seen all three happen when EGL graded "J" color stones have been submitted to GIA. In smaller sizes, and lower grades there's a lot less at stake.
If it's a 2ct plus G color- or whatever stone that's more than about $3000- the stakes are completely different.
In any event, MONEY BACK GUARANTEE is essential for those who choose to roll the dice with the non GIA reported stones.
Please make sure that whoever is selling this EGL graded stone admits that the grading is considered soft by the trade themselves.
If they deny that, you have somethign to worry about, in general, in my opinion
 
Charmy,
Thank you SO MUCH for posting that link. I had not read the Grading Lab Survey and it was most helpful.

D&T, I am glad to know that there is someone else out there who approaches things as I do. Yet I also know as you stated that "running the numbers" is only so good, and then your eyes have it. Which is again why I won't buy without looking at stones in person.

Rock, I completely agree and with the one vendor I've gone back to a couple of times, the EGL grading has already been discussed at length and is on the table. I know it helped tremendously that I had already read as much as I did prior to going in there, and on my second visit, I had my Ideal Scope, Loupe and tweezers. :naughty:

One other thing I forgot to mention, is that when I went to the appraiser last week, I was able to see a set of master stones for color. It was more helpful than I can express - all the same carat weight and shape, in the colors from D-J. I had pored through GOG's vimeo of the same thing, but seeing it in person was a real help. I attached them below. From the left: K, J, I, H, G, F.

Master Set.jpg
 
ImpatientOne said:
I m not sure what you are trying to compare. The big concern that many of us here have, is that EGL is more lenient with their grading. For example, take two of the G, SI1's. One graded by GIA is $8654 per carat. Graded by EGL they run ~$6500 per carat. The problem is, with the more lenient grading from EGL, that G SI1 graded by EGL could potentially be a I I1 if it were graded at GIA standards...
Click to expand...

well, from what i remember from the sample study that pricescope did a few years back and is linked here somewhere... egl usa's clarity grading was pretty much the same as the gia's and when it was off it actually was MORE stringent than gia's. however, you are right re: color... gia tended to grade color more strictly than egl usa.

so many people are harsh toward egl usa. i often read about the clarity grades being way off but according to the study done here that is not the case.

i just so happen to own an egl usa i color, si1 and i'll tell you that for the life of me, i cannot see any inclusions. period. i've had jewellers looks at it and assume it's a vs. i'm very happy with my egl usa diamond ;))
 
each one of my wife's .72ct diamond stud cost about the same price.

a) GIA H SI1
b) EGL-USA G VS2
 
Anne :) said:
by denverappraiser » 05 Sep 2010 15:15
If you want to compare stones sight unseen using only lab data, the FIRST criteria is the choice of lab, not clarity/color/weight. Compare GIA's against other similar GIA's, EGL-USA's against other EGL-USA, EGL-International against other EGLI's etc. There simply is not a conversion from the way one lab grades to the way the others grade. Even within a particular lab there are a fair amount of issues to consider and each grade represents a range of possibilities but you can come a lot closer to comparing apples to apples if you do it this way.

Anne,

If you are considering EGL stones to try to save money or because you think you can find that rare one that was graded the same as GIA yet is still discounted, your odds are slim to none and most likely you will be fooled into thinking you got a bargain when the exact opposite is much more likely.

Cutters and wholesalers are very smart, they have to be to survive in this competitive business. If they think sending a stone to EGL instead of GIA will bring in more money or make a stone easier to sell they will do it. An I1 sent to EGL to get SI2 or SI3 would be a good example of this. Also a GIA J can often fetch less than an EGL G or H so it gets sent to EGL.

The dealers and wholesalers know the tricks, they know the true value of the stone and what the cutter has asked for it. You the consumer have very little information and you are banking on some very weak trends to try to buck the odds of their experience.

Also I think Cut (other than HCA) was largely ignored in your data and is much more complicated than a simple HCA score, why would a cutter of a fine make round send their stones to a second or third tier lab? Not only is EGL soft on color and clarity but also stones that don't make at least GIA Very Good for Cut have a much higher likelihood of being sent to EGL.

Analyzing the data charts is fun and interestng but at this point I'm not sure what your goal is or expanding your search to consid EGL graded stones is going to help you achieve it. You are right you aren't buying the paper, but the paper gives you a confident indication of the quality of the stone, which you won't have unless you have spent considerable time educating your eyes on diamond appearnace in all different lighting conditions.
Click to expand...
Click to expand...
 
I think I am trying to put some black and white to a very subjective system. Because I am so numbers-oriented, I think I find comfort in being able to analyze data and come up with a "good" answer. I -know- in my head that diamonds are such a sliding scale with so many variables that even comparing two diamonds from one lab is nearly impossible as there are rarely two exactly alike.

My struggle has been to understand why EGL gets such a bad rap, when you see stones in person that don't look as bad as they seemingly would be based on all the bad press. But honestly I vascillate so widely between my approach and what I want to do that I dont' even know where I'm going to end up. Part of me wants to really shop for the center stone, I have the tools and I am getting there on the knowledge; part of me wants to pay a premium to someone from PS who I know sources the best diamonds and just let them handle it. Of course then I have to figure out what I want <sigh> and I'm not there yet either. Solitare? Five stone?

Problem is no amount of posting is going to help me figure out what I want first, which is what I have to do before I can really go much further. Just about every new ER posting makes me go "oooh! I love that"

It's a journey, that's for sure.
 
for the record, my egl usa stone was bought at a pawn shop. i'm guessing that in a situation where someone pawns a ring w/out a grading report, and the pawn shop's big enough, they send their stones out en masse to egl usa. while looking at the stone i bought, i noticed all the other stones' grading reports i was shown were egl usa WITH (and this is where i clued in) similar grading dates. AHA!

sooooo, if you're in a situation like mine, my stone easily could've had a gia report and the owner lost it, it was stolen, whatevs.

the thing to keep in mind is that a diamond is a diamond is a diamond is a diamond. there. said it! i've never had a soul ask me who graded it (except here, of course) and it sure is a pretty rock, so hey, i'm very satisfied AND i got a killer deal :$$):

i strongly feel you can get some great deals on a egl usa rock. the thing is, you've gotta know what you're looking for with a lot of education backing you up. if you account for color being off a grade or so, calculate the cost of a gia/ags diamond of the lower color and compare with that. re: clarity, egl usa tends to be a hair stricter (at least according to the study done by here pricescope).
 
EGL, especially EGL International, gets a bad rap because they are seen as inconsistent. Sometimes a stone graded on the GIA scale as an I-1 will be graded SI2, sometimes SI1, sometimes I-1. The same happens with color. Sometimes GIA-H will mean EGLI-G, sometimes, EGLI-F, sometimes EGLI-H. If you're going strictly off of the paper rather than personally grading the stone or by hiring your own expert to grade it for you, you just don't have enough information to compare. On the other hand, if you ARE relying on your own expert (or your own expertise), what EGLI thought of it is basicaly irrelevant.

As has been pointed out above, you are not the first person to consider this issue, even in terms of that particular stone. In partiicular, someone chose that particular lab, and they didn't make this choice arbritrarilly. They could have used any lab in the world that they wanted and they chose that particular one because they felt that they could get the maximum price by attaching that particular pedigree. This decision was made by an industry insider, probably at the cutting house level, but it has since passed through the hands of several other experts, each of which had the opportunity to resubmit it to a new lab if they thought it would enable them to raise the price. It's not that it's impossible to game this system and win, it's that you're going up against well practiced insiders who HAVE actually seen the stone and so you are at a serious competitive disadvantage.
 
anitabee said:
for the record, my egl usa stone was bought at a pawn shop. i'm guessing that in a situation where someone pawns a ring w/out a grading report, and the pawn shop's big enough, they send their stones out en masse to egl usa. while looking at the stone i bought, i noticed all the other stones' grading reports i was shown were egl usa WITH (and this is where i clued in) similar grading dates. AHA!

sooooo, if you're in a situation like mine, my stone easily could've had a gia report and the owner lost it, it was stolen, whatevs.

the thing to keep in mind is that a diamond is a diamond is a diamond is a diamond. there. said it! i've never had a soul ask me who graded it (except here, of course) and it sure is a pretty rock, so hey, i'm very satisfied AND i got a killer deal :$$):

i strongly feel you can get some great deals on a egl usa rock. the thing is, you've gotta know what you're looking for with a lot of education backing you up. if you account for color being off a grade or so, calculate the cost of a gia/ags diamond of the lower color and compare with that. re: clarity, egl usa tends to be a hair stricter (at least according to the study done by here pricescope).
Click to expand...

I'm sure you got a great deal- and a lovely diamond.
If you ever try to sell it, the first question most dealers will ask is who graded it.....

If you're not a diamond grader- and very sure of how to grade, EGL is a very risky proposition.
 
There is nothing inherently *wrong* with EGL diamonds. What is wrong is that the lab is inconsistent in its grading and so consumers do not know that they are paying fair value for the diamond they purchase -- they cannot reliably compare to GIA/AGS nor can they reliably compare to other EGL graded stones! That is why EGL has a "bad rap" on PS. It is really quite simple.
 
well, i suppose if i want to sell it i'll simply get it graded by gia!

i agree, selling with a gia grading report is obviously easier HOWEVER... buying an egl usa, if you know what you're doing, CAN result in a deal!
 
actually, this is why i love pricescope so much. i've learned soooooooo much over the many years i've lurked here that i feel well-armed with info. this site is priceless!

and hey, if i ever get my egl-usa graded by gia or ags i'll immediately post the results and see how close my egl graded rock compares. it would be interesting to find out. hmmm...
 
anitabee said:
actually, this is why i love pricescope so much. i've learned soooooooo much over the many years i've lurked here that i feel well-armed with info. this site is priceless!

and hey, if i ever get my egl-usa graded by gia or ags i'll immediately post the results and see how close my egl graded rock compares. it would be interesting to find out. hmmm...
Click to expand...

anitabee said:
well, i suppose if i want to sell it i'll simply get it graded by gia!

i agree, selling with a gia grading report is obviously easier HOWEVER... buying an egl usa, if you know what you're doing, CAN result in a deal!
Click to expand...

How would one know what they are doing?
The highest reasonable standard for an appraisor is +/- 1 color grade from the GIA grading report, and that is for a loose stone.
If looking at it set or faceup +/- 2 grades or more would be more realistic.

Appraisers just don't reproduce the diamond dock, carefully selected lighting, a full range of diamond calibration stones, white tray and a carefully selected viewing distance and a calibration set close to the size of the stone.

Most appraisers have an incomplete(with gaps) set of CZs in one size that probably get checked with a master stone set once a year. I don't know how you could be sure you got a good deal unless you sent it to GIA or AGS or compared side by side with a similarly priced GIA/AGS stone in person.
 
ChunkyCushionLover said:
Appraisers just don't reproduce the diamond dock, carefully selected lighting, a full range of diamond calibration stones, white tray and a carefully selected viewing distance and a calibration set close to the size of the stone.
.
Click to expand...
Actually, I do exactly that, including a full set of diamond masters from E-M inclusive and an O/P and U/V master thrown in just for kickers if I'm in the lower colors. I thrown in yearly color vision testing by the way. I'm actively looking for a Z master but that's sort of the holy grail for appraisers. There are a lot of 'appraisers' out there who aren't properly equipped or trained for the job and I know what you mean by your advice but we're not all the same.
 
denverappraiser said:
ChunkyCushionLover said:
Appraisers just don't reproduce the diamond dock, carefully selected lighting, a full range of diamond calibration stones, white tray and a carefully selected viewing distance and a calibration set close to the size of the stone.
.
Click to expand...
Actually, I do exactly that, including a full set of diamond masters from E-M inclusive and an O/P and U/V master thrown in just for kickers if I'm in the lower colors. I thrown in yearly color vision testing by the way. I'm actively looking for a Z master but that's sort of the holy grail for appraisers. There are a lot of 'appraisers' out there who aren't properly equipped or trained for the job and I know what you mean by your advice but we're not all the same.
Click to expand...

Neil if you follow most or all of the measures described in:
--------------
COLOR GRADING "D-TO-Z" DIAMONDS AT THE GIA LABORATORY
GEMS & GEMOLOGY Winter 2008

DD and verilux lamps

Including:

Boiling your masters in Sulfuric Acid monthly.
Replacing the lamps every 1800 hours

and about a 100 other very small details like sitting 12 - 15 inches form the diamond at a 45 degree angle from the plain of diamond and light source.
-----------------------------------------------------------------------------------------
I tip my hat to you.

You are certainly no ordinary appraisor and few of us are lucky enough to have someone of your standards for precision to appraise our diamonds locally.

Regars,
CCL
 
Hi Anne,

I think you have some very interesting data here. In my opinion the best way to find out what you are looking for is to run a regression analysis. Are you familiar with this methodology? If so I think the best way would be to gather as many similarly graded diamonds and using price as the dependent variable, make sure you have independent variables for all of the important value factors, including Gem Lab. By doing this you should get, within a certain tolerance, the price difference between the labs.

Good luck,
 
FWIW, I love your data-based methods!

For real kicks, how about running a regression for RBs (control for cut quality, color, clarity, and carat size as a function of price -- ordered factors all) and throw in a dummy variable for each lab (and if you want to get real crazy, add an interaction term for each lab / cut / color / clarity grade. I'll bet you have the biggest coefficient of variation around the EGL labs (reflecting the common wisdom that EGL diamonds have inconsistent grading).
 
As a seller who truly hates misrepresentation in my chosen profession, I get uncomfortable anytime a thread takes the turn of
"I bought an EGL graded diamond and got a great deal- if you know what you're doing you can get a deal on EGL graded stones"

Please don't misunderstand this as a criticism of anyone who's said something like that- but I can't stress strongly enough that such sentiment can lead innocent consumers to very bad decisions.

I like to point out that sellers know the tricks of the trade, and how EGL is viewed. So, it's really more about sellers, and how they represent these stones than the stones themselves, or even EGL itself.

As an aside, it seems to me that almost every time we want to buy an EGL graded diamond from a cutter, the price seems to be exactly in line with what the stone would grade as if GIA had done the grading.
 
antelope1 said:
For real kicks, how about running a regression for RBs (control for cut quality, color, clarity, and carat size as a function of price -- ordered factors all) and throw in a dummy variable for each lab (and if you want to get real crazy, add an interaction term for each lab / cut / color / clarity grade. I'll bet you have the biggest coefficient of variation around the EGL labs (reflecting the common wisdom that EGL diamonds have inconsistent grading).
Click to expand...

Thanks for the flashback to grad school and econometrics.
 
Aren't there hand held devices to measure the color in a diamond
color should be measured easily in an objective way with all the advanced technology we have are there such devices ?
 
Here is an article that is old from 1999 when i was searching for an objective way to measure the color

Manufacturers of the two most popular color-grading machines, Gran Technologies of Israel and Austron Corp. of Santa Clarita, Calif., say they’re working to overcome such shortcomings and claim to be accurate to within a half or a third of a GIA color grade. Both companies want to bring their machines more in line with how people see diamond color. To that end, manufacturers try to calibrate their machines according to GIA’s color-grading standards. “Of course we try to match the GIA’s grading,” says Paul Gran, president of Gran Industries. “After all, it’s the industry standard.
Click to expand...
the link:
[]http://www.jckonline.com/article/291832-Diamond_Grading_with_Bells_and_Whistles.php[]
when i searched for those names nothing came back.
 
Thanks Tom, Thanks antelope.

Guess I have a weekend project, been toying with the regression in Excel. Now to figure out the data sets.

Price? $5000? Seems to be a good average for 1 ct stones, plenty of data to pull, and a good range of carat, color and cut.

Any other thoughts on this!?
 
You must log in or register to reply here.
GET 3 FREE HCA RESULTS JOIN THE FORUM. ASK FOR HELP
Jewelry Blog
PriceScope-Concierge-Ad
Find prime cuts.
Top