Accuracy of Tiffany Certification v. GIA

[AdamSklar]

To anyone out there with both a Tiffany''s cert and GIA cert for the same round brilliant, could you please let me know whether Tiffany''s Excellent Cut shows up as Excellent on the GIA cert as well? I just want to see how Tiffany''s cut grades measure up with GIA''s.

If, for some reason, you have a Tiffany''s cert and a AGS cert, I''d be interested to see how those stack up as well.

Thank you!

Adam

 

[Garry H (Cut Nut)]

I imagine that many senior Tiffany gemo''s (who are probably ex GIA lab staff or GIA GG''s) find GIA''s lab to be employing under skilled staff (perception or reality?) and often question grading calls.

So they probably made a decision to provide their own more consistent and less likely to damage their brand (in their opinion) internal graders. In my own retail company at any 1 time we have maybe 5% of our stones on offer as a lower grade than the lab report.

I know a company that runs the best most honest and accurate lab, and they only grade thei own diamonds that are sodl on the basis of their own internal grade. It was like that for 3,000years and only changed 50 years ago.

It is possible that in 50 years there might not be labs. GIA grading costs about 2X more than cutting and polishing for most diamonds. I imagine technology will one day replace such sillyness.

 

[diagem]

Date: 7/6/2007 9:12:13 AM
Author: Garry H (Cut Nut)
I imagine that many senior Tiffany gemo''s (who are probably ex GIA lab staff or GIA GG''s) find GIA''s lab to be employing under skilled staff (perception or reality?) and often question grading calls.
So do I..., but Tiffany has the luxury to put their reputation behind the decision to not agree with GIA''s grading calls (in both direction...)

So they probably made a decision to provide their own more consistent and less likely to damage their brand (in their opinion) internal graders. In my own retail company at any 1 time we have maybe 5% of our stones on offer as a lower grade than the lab report.
What is the % of higher grades ''than the lab report''?

I know a company that runs the best most honest and accurate lab, and they only grade thei own diamonds that are sodl on the basis of their own internal grade. It was like that for 3,000years and only changed 50 years ago.

It is possible that in 50 years there might not be labs. GIA grading costs about 2X more than cutting and polishing for most diamonds. I imagine technology will one day replace such sillyness.


Sounds like a "dream"...., do you really think technology will be able to grade clarity correctly?

 

[AdamSklar]

Dia Gem-

That is the thrust of my question: What percentage of Tiffany Excellent cuts would grade lower on a GIA report.

Just for fun, I went into a local Tiffany & Co. with my ideal scope and looked at a random sample of 10 round brilliants. All 10 were triple EX according to the Tiffany certification. I did not get to look at any GIA certs. Of the 10, 4 diamonds had too much light leakage under the table, which came as a little bit of a surprise to me.

Granted, 10 stones is hardly a representative sample size, but that got me thinking nonetheless. I started digging around on the internet for some numbers on Tiffany Excellent cuts and plugging the data into Facetware. A significant number of those stones came out as Very Good. For instance, two stones with these numbers were considered Excellent by Tiffany and Very Good by GIA (I chose these stones because they required the least rounding on Facetware):

Total Depth: 62.3%| 62.9%
Table: 56%| 54%
CA: 34.5 degrees| 35.5
PA: 40.8 degrees| 41.0
Culet: None| None
Girdle: Thin to medium| Med-SlThk
Symmetry: Excellent| Excellent
Polish: Excellent| Excellent

While it comes as no shock that GIA would give an Excellent rating to the steeper/deeper stone, I was a little surprised that the first stone (the one with a total depth of 62.3) graded at VG. I'm interested in seeing whether the discrepancies between the Tiffany cut grades are with Facetware or the actual GIA certs. I'd also be interested in seeing any gem files on the two stones to see how Diamond Calc views them.

*I just want to note that I have nothing against Tiffany. They may very well grade harder on color/clarity than GIA. From my VERY limited experience, however, their cut grades seem a bit on the lax side. They have a good amount of deep/border-line deep stones that make their Excellent grade, even with questionable PAs.

 

[WorkingHardforSmallRewards]

Yea, there has beena little bit of discussion recently as one of the PS members is looking at Tiffany diamonds. look up the recent threads (in the last two pages) by Kissmark. It sounds like you would have some experiences to offer him and some better understanding of the range of cuts offered by Tiffany''s. I myself tried to defend Tiffany''s and what seems to be their common cut...but I don''t really believe it myself

but I also don''t have any where I can go and say "hey, can I see a steep/deep combo" and Tiffany''s is to far away for me to drive for that now that I have more information than the last time I was over in charlotte. So anyway, I cant say! but, I think kissmark could use your experience and knowledge of Tiff cuts!

 

[AdamSklar]

Sorry, I misspoke. Facetware graded both stones I listed above at VG.

As for Kissmark, I''d love to help but I''m nothing more than a hack. I''m afraid my advice wouldn''t be too helpful given my limited sample size of Tiffany''s stones. Just generalizing from my experience, however, Tiffany''s RBs aren''t terrible. Some are quite nice. The ones that had too much leakage (at least for my tastes) had a visible difference to the naked eye. Kissmark would do well buying an ideal-scope and bringing it into the store. The salesperson I had was quite accommodating.

Just for the heck of it, I entered the numbers from Kissmark''s stone, a Tiffany''s Excellent, into Facetware. The stone graded out at Excellent as well. Here are the specs:

Total: 62.4%
Table: 56%
CA: 35.4
PA: 40.9
Culet: None

The depth/CA combo has me a tad concerned, but nothing that a visual inspection of the stone won''t assuage. Again, I''d be interested to see a gem file comparing Kissmark''s stone to the first stone I listed (CA: 34.5, PA: 40.. If anyone could help me out, I''d really appreciate it.

Adam

 

[Nicrez]

Adam, not sure what your stury is hoping to achieve...?

You would be interested to know that TIffany sends over 10,000 stones every single week out of their lab to their retail stores into market, sometimes more. Monthly, we are looking at over 100,000 stones on a very slow week. Of the stones that are in the store where you were there are stones that are graded years ago, to stones likely graded within the year. From the many years stones have been selling at Tiffany, you have had changes in management and changes in lab grading policies.

The standards have changed and with every year the standards have tghtened. Never once has any of the TCO stones been put through an ASET machine, or other light leakage testing. They WILL NOT and this is not only based on the fact that their production is far greater than can be graded (often causing a backlog to market), but it''s foolish to expect these stones to fit a standard of cut that is unnecessary. I have personally seen an AGS000 stone next to a TIffany stone. For the same price no less. I prefer the TIffany stone.

If what your research is attempting to prove is that TCo''s diamonds are not ASET approved stones, I will tell you you are right. But if you take a TCo stone to the 47th street market, they all will be graded within the top 10% of stones on the market. Hands down. The market includes Zales, and Walmart, as well as AGS000 stones, FYI.

If you are trying to figure out TCo quality, that will take a judgement call on the most recently graded stones which are likely not even in stores on a wide scale. Even then, you can barely scratch the surface of a true test.

I would say that Tiffany Labs disagree with the GIA about as often as Gary predicts. From what I notice in my dealings with GIA, I often disagree with their color and clarity. Color about 10% of the time, and clarity about 5%. But their color machines are not always well calibrated in my opinion.

Gary, there are machines being tested right now that based on the laser concept of Sarin that are mapping out inclusions and abnormailites in the cell structure of stones that are checkable by graders, but based on a digital automation of grading procedures. Still human element is needed to override any graining to be determined from feathers, or the like, but the software is out there, and my guess is in 20 years it will be in most large labs and likely fully-automated.

By the way, I had a stone graded at GIA that cost $1,820 to grade. That hurt. Their prices (even for rechecks) is silly... I like how they state that wait is 8-10 business days and ends up being MONTHS. My favorite was a guaranteed 2-3 business day turnaround that took them 15 business days to get back... well done.

 

[WorkingHardforSmallRewards]

You work for Tif? I love this site. Even though I will never meet you! it makes me happy!...can I ask, exactly who are you, I am quite curious?

Also, just to defend that guy (I don't remember his name and its 0243am, so I am not going to check it) I think that he was concerned about there being a relatively wide variance of excellent cut grade parameters, which seems to be the case. Given that the cuts are not all within a very small parameter it only makes sense that it would be necessary to determine which of these "wide" cuts your eye prefers, rather than solely trusting the Tif. name to pull you through the process (though you could of course do that and I am sure that most anyone would be happy with it) .

Also, it seems based on my limited knowledge and from mt dealings with Tif down in charlotte nc, that many of the cuts are not designed for maximum light return. That isn't to say that they aren't beautiful, but if a person decided that their eyes were keen on a maximum light return and a certain combination of angles then this would obviously be a concern and something worth noting.

I really doubt that this person was trying to insult the Tif name (that would, after all, be suicide to his own) but rather expressing shock and surprise that Tif cuts don't match the traditional TIC a little more closely and that they seem to be off from current AGS grades and what we learn to be "ideal" here on PS. Naturally, to us PS educated people, that would be very confusing, as Tif=ideal but ideal=X and Tif does not equal X . Myself and many other self-educated consumers have a very limited knowledge and I know people like myself (even being WAYYY to poor to make a sizable enough purchase from Tiffany) would love to hear more about why Tiff chooses the combos that it does and why they are selected as Excellent cut candidates.

And, finally, I am sure that, as you say, Tiff. cut requirements are growing and changing every year, then it would also be true like the poster suggest right? that some of the diamonds are still on the market, but might not be up to current ideal standards that we on PS are aiming for today (though it might not be necessary to do so as they may well be just as gorgeous) and thus if we truly want one of those then it would only be prudent to inspect each Tiffany diamond heads up to find just the right one for us based on what we want and expect, rather than purchasing a slightly older cut grade that is beautiful in its own way, but not up to one's own personal desires. Thus I honestly appreciate the heads up, and I think it will be very beneficial to Tif. Consumers out there studying on PS to be aware that they might want to observe some of the different Tif Combos and decide which one they like the best for themselves and pursue one of those rather than just a random Tif.

(I am mostly posting this as it looked like fun to try to get to chat with you

)

Also, I think people need to consider carefully about having grading done by technology. Alot of the value of diamonds is the sentimental element of it. Otherwise we would all get Synthetics or other similar substitutions for thousands less. And, to me at least, having a diamond that has been inspected by a group of people and determined to be a certain color, clarity and cut grade, is a huge part of the value of it. It gives diamonds that somewhat romantic and valuable element, whereas if it was just machines evaluating it I might care much less if it was a naturally forming genuine diamond or not.

 

[AdamSklar]

Nicerez-

I apologize if I offended you, that was not my intent. I'm not a member of the trade, so I have no vested interest in proving whether GIA Ex, AGS000 or Tiffany is the superior cut grade. I'm just a corporate attorney who is in the market for an engagement ring. To the extent that I have any interest in the three aforementioned organizations, it is a slight bias in Tiffany's favor (as the brand is important to my girlfriend).

My purpose for starting this thread was simply to satisfy a little intellectual curiosity. As I mentioned earlier, I want to see how often Tiffany Ex cuts receive a lower GIA grade. I'm not trying to determine which organization erred, although I can see how you would get that impression given the way I named/titled this thread. To be absolutely transparent, here's what I hoped to find out:

(1) How often Tiff's EX cuts receive a GIA grade of VG (or lower);

(2) Where the discrepancies lie between the two; and

(3) How often there are discrepancies between a Facetware-projected grade and the one actually conferred by GIA.

In short, I'm just trying to get informed. I appreciate the information you provided. Again, I apologize if I offended you.

Adam

*Just wanted to note that I'm interested in this information independent of my search for an engagement ring.

 

[JohnQuixote]

Date: 7/6/2007 12:06:55 PM
Author: AdamSklar

Total Depth: 62.3%| 62.9%
Table: 56%| 54%
CA: 34.5 degrees| 35.5
PA: 40.8 degrees| 41.0
Culet: None| None
Girdle: Thin to medium| Med-SlThk
Symmetry: Excellent| Excellent
Polish: Excellent| Excellent

I'd like to suggest rounding could be muddying the waters here. At 62.3% depth a diamond with 56/34.5/40.8 has a girdle near 2.3% (VG).But with C/P at 34.7/40.9 the girdle is reduced by 0.2% and that diamond would then receive EX.Similarly the second diamond has table/ca/pa within the GIA EX range (though deeper than what we typically see on PS) and if you move either angle up one tick facetware puts it back ‘in range’ for EX.Another rounding or girdle discrepancy perhaps? Either way, for a strictly technical evaluation it would be helpful to know girdle % since different organizations measure differently and verbal descriptors like Tn-Md don’t imply the same thing.

It's always fun to discuss this stuff, I'm just trying to ‘keep it real’ from a numbers-chasing standpoint. On paper one tick in crown angle may not be visually perceptible at all, but will place a diamond on one side or the other of a grade, for better or for worse (insert ad for AGSL here).

Let’s not forget institutions like TCo were among the very first in the world to back cut quality.They were clients of Henry Morse, and selling the American Ideal cut years ahead of Tolkowsky.Without those institutions that supported advances in cut quality using their eyes, long before scans & reflectors, we wouldn’t enjoy the ‘niches’ we have today.

 

[Nicrez]

Date: 7/7/2007 1:54:50 PM
Author: AdamSklar
Nicerez-

I apologize if I offended you, that was not my intent. I''m not a member of the trade, so I have no vested interest in proving whether GIA Ex, AGS000 or Tiffany is the superior cut grade. I''m just a corporate attorney who is in the market for an engagement ring. To the extent that I have any interest in the three aforementioned organizations, it is a slight bias in Tiffany''s favor (as the brand is important to my girlfriend).

My purpose for starting this thread was simply to satisfy a little intellectual curiosity. As I mentioned earlier, I want to see how often Tiffany Ex cuts receive a lower GIA grade. I''m not trying to determine which organization erred, although I can see how you would get that impression given the way I named/titled this thread. To be absolutely transparent, here''s what I hoped to find out:

(1) How often Tiff''s EX cuts receive a GIA grade of VG (or lower);

(2) Where the discrepancies lie between the two; and

(3) How often there are discrepancies between a Facetware-projected grade and the one actually conferred by GIA.

In short, I''m just trying to get informed. I appreciate the information you provided. Again, I apologize if I offended you.

Adam

*Just wanted to note that I''m interested in this information independent of my search for an engagement ring.

I am not at all offended, but somewhat perplexed at the end to the search. If you look back at all the Tiffany posts (hundreds by now I am sure) you will see tha of the more recent, it has been determined that you will never get an accurate answer that will be researched enough if you use TCo as a measuring stick. Their output is way too voluminous to get an accurate feed.

They deal is the best cut grade for the amount of stones they sell. They sell A LOT. They are known to be the top 10% of the trade. Color, clarity, cut grade are all factors for their selection process. Here on PS, there cut grade is the top 1% likely, but not when it comes to color or clarity. The focus is on actual measurement of stones. It''s a different market, in my opinion.

FOr those who have less time or inclination to search each stone they see, TCo is good for the descriminating consumer who wants to leave the gemology to the company and have a name and guarantee behind it. And that is what people pay for. Peace of mind. Not always, but so consistently. Like a chain you can trust in high end diamonds.

your research is valid and important, it''s just being done on too small of a section of the market, and it''s something akin to studying the Sistine Chapel in 5 minutes wth a loupe. You are getting grains of sand, and not the beach.

I do not work for Tiffany, so I am a member of the jewelry trade, but not the diamond trade. It''s fascinating and I used to work with diamonds, but have opted to let the settings and pieces speak for themselves. I like the art behind them, as much as I like the art of cutting. I am into antiques and old stones, from OEC to cushions from eras past. Modern round brilliants to me are too exact for my taste, personally. Although I like to read the pros comments on the site and I learn the finer details of software and studies through the geniuses of PS who so generously post on their free time. There is no forum like this one!

I have many contacts within the industry, so what I gather is from firsthand and second hand sources. I can not always be of help, but when it comes to quality and cut grading for TCo, I have quite a bit of information I try to share, and I do from time to time.

As I see it, I suggest if you buy from TCo, the best way to find a diamond you like is to SEE it. It must speak to you. Remember these are luxury items, NOT commodities that are all the same and quantifiable (some would argue). But when searching PS for stones of the 1%, you will be greeted with numbers, Sarins, ASET images and all sorts of test that the stones undergo. Why? Because the average consumer on PS understands these and asks for them. Not at TCo. Don''t be surprised to get resistance. It''s like walking into an art gallery and asking if the canvases are made of biodegradeable fiber...? It''s almost sacreligious, as TCo prides themselves on providing people with the service of bringing you a guaranteed certain quality BEFORE it leaves their lab. And they do. They may not be PS standard of cut, but they will CERTAINLY be EX at GIA''s cut standards, or at the least VG (for Rounds). Of course larger stones above 3ct and shaped stones are not included in this.

I come to the table with a very different point of view on diamonds, as I have seen some 60/60 (HORROR!) stones I prefer far more than the standard PS precision cut, and I also buy stones based on life, and do not ask for Sarins when buying, only GIA certs to verify color and clarity. I have spent many days pouring over GIA graded, and ungraded diamonds. I have in my time seen thousands of diamonds, and after seeing so many, I feel that the eyes are keen enough to detect irregularities that machines can not always find. And sometimes when you just have numbers, you don''t have a case for a good or bad stones, you just have a bunch of numbers...

I respect the work of these people, and I admire their determination to make diamond and their research as scientific and exact as possible, which I greatly enjoy learning about. My approach, however will be from an artistic (sometimes practical) point of view when buying and not so much scientific...

 

[AdamSklar]

John-

Thanks for chiming in. Seems likely that girdle thickness is the culprit. Doesn''t appear that optical performance will be adversely affected though. The stones probably just pack a little extra weight at the girdles, which I don''t think is necessarily a bad thing in Tiffany''s classic setting.

Nicerez-

I completely agree with your assessment regarding the limitations of my "study." In fairness, I''m not trying to conduct anything close to journal-quality scientific research, I''m just trying to scratch an intellectual itch. The whole point is moot anyway, given the number of actual responses to this thread.

I also agree that Tiffany and PS cater to different segments of the market. Unfortunately, I happen to be caught in between those two segments. I need the Tiffany brand and the PS quality. I''m just trying to determine whether these two are mutually exclusive, which I suspect is not the case.

I''m determined to buy at T&Co because of their excellent service (Harry Winston absolutely ignored me), but I want to get the best T&Co. diamond that I can. Contrary to what you opined, Tiffany''s salespeople have been infinitely patient with me, even with my ideal-scope in tow. Maybe it''s because I gave them my budget. I don''t know and frankly don''t care. Hopefully with their continued patience I''ll be able to find what I''m looking for -- something that I''ll be proud to present my girlfriend.

Adam

 

[junior35]

Date: 7/7/2007 11:37:18 PM
Author: AdamSklar
John-

Thanks for chiming in. Seems likely that girdle thickness is the culprit. Doesn''t appear that optical performance will be adversely affected though. The stones probably just pack a little extra weight at the girdles, which I don''t think is necessarily a bad thing in Tiffany''s classic setting.

Nicerez-

I completely agree with your assessment regarding the limitations of my ''study.'' In fairness, I''m not trying to conduct anything close to journal-quality scientific research, I''m just trying to scratch an intellectual itch. The whole point is moot anyway, given the number of actual responses to this thread.

I also agree that Tiffany and PS cater to different segments of the market. Unfortunately, I happen to be caught in between those two segments. I need the Tiffany brand and the PS quality. I''m just trying to determine whether these two are mutually exclusive, which I suspect is not the case.

I''m determined to buy at T&Co because of their excellent service (Harry Winston absolutely ignored me), but I want to get the best T&Co. diamond that I can. Contrary to what you opined, Tiffany''s salespeople have been infinitely patient with me, even with my ideal-scope in tow. Maybe it''s because I gave them my budget. I don''t know and frankly don''t care. Hopefully with their continued patience I''ll be able to find what I''m looking for -- something that I''ll be proud to present my girlfriend.

Adam

Adam,by now you probabely know that oftentimes stones are resubmitted to the GIA for recheck on color and/or purity.Sometimes,stones will get the better grading.This means that at any one time there are out there plenty of "borderline" GIA cerificates.
In the case of color and purity grading ,T&Co nearly always prefers to err on the safe side.It''s obvious,it''s not in their interest to risk their brand by pushing borderline colors and purities.At least on that point the consumer can have full confidence.

 

[WorkingHardforSmallRewards]

How consistent has the color and clarity of GIA grading been over the years since founding? any notable changes?

 

[Kissmark]

Date: 7/6/2007 3:37:14 PM
Author: AdamSklar
Sorry, I misspoke. Facetware graded both stones I listed above at VG.

As for Kissmark, I''d love to help but I''m nothing more than a hack. I''m afraid my advice wouldn''t be too helpful given my limited sample size of Tiffany''s stones. Just generalizing from my experience, however, Tiffany''s RBs aren''t terrible. Some are quite nice. The ones that had too much leakage (at least for my tastes) had a visible difference to the naked eye. Kissmark would do well buying an ideal-scope and bringing it into the store. The salesperson I had was quite accommodating.

Just for the heck of it, I entered the numbers from Kissmark''s stone, a Tiffany''s Excellent, into Facetware. The stone graded out at Excellent as well. Here are the specs:

Total: 62.4%
Table: 56%
CA: 35.4
PA: 40.9
Culet: None

The depth/CA combo has me a tad concerned, but nothing that a visual inspection of the stone won''t assuage. Again, I''d be interested to see a gem file comparing Kissmark''s stone to the first stone I listed (CA: 34.5, PA: 40.. If anyone could help me out, I''d really appreciate it.

Adam

Adam and Workinghard thank you both very much! When you say Depth/CA combo had you concerned, can you elaborate? What is wrong with it? Is it too deep? or should the CA be smaller? bigger? Thanks so much!!

 

[WorkingHardforSmallRewards]

What I took away from this thread is that the questioned cut combinations aren't necessarily in the top 1% of cuts when basing that cut grade on light return and scientific analysis of angles.

So while Tif. doesn't insure that top 1% it will ensure the cut will be in top 10% of cuts and light return.

That is partially what the HCA is meant for, if it scores lower that doesn't mean the cut is bad, or that it isn't in the top % of cuts, but it does imply it is not one of the "Super Ideals" that is always talked about here on PS.

thus it looks to me like if you are looking at Tiffany diamonds and can go to stores you should go and inspect some of the different angles and combinations and see how you feel about them. tiffany seems to carry alot of old stones with different cut parameters and new one's with focus more similar to modern AGS 0 cut parameters.

which means that they will have a wide variety of cuts. Some of them will be up to PS super ideal cuts and AGS 0 cuts, others will not. Take a look and decide if it is necessary for you to seek out a Tif with the "Super IDeal" cut, or if you would be happy some different set of parameters available at Tif, or perhaps you can't see any real difference in any of the "top 10%" cut diamonds, and thus choosing them based on color, clarity, price, and "excellent Tiffan cut grade" is all you really need to be concerned with, rather than the minutia of angles. But only you can truly decide that for yourself.

 

[AdamSklar]

Sorry for the late response, but I agree with everything WorkingHard said. They''re nice looking stones, most of them are just not the super ideals that pricescopers look at.