Discuss Review of GIA Foundation article posted in the Journal

Gary

www.diamondexpert.com

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Raffaele Zancanella

........... Karl has joined the diamond trade and is now posting as Karl_K

The price forecasting at the end of the article prices lab paper by it’s weight in diamonds. Now, that’s a deal, no ?  Not to mention that cut is entirely made not born like carat, color and clarity presumably are.

At a first read,  a couple of its from the article proved particularly useful to navigate the tangle. Here they are, starting with an eye opening question:

How fair is the system ? Well…
“I question the validity of this grade that would apply to the worst 1% of certified diamonds based on a survey conducted on Rapnet on 11/19/2004. There were only 441 plus 1.00ct rounds with depth % greater than 69% listed out of approximately 40,000 round stones searched by the same criteria. Surely the lowest grade in a 5 grade system should be set to reflect around 10 to 20% of the goods in the market?”

Can buyers possibly see more in their diamonds than GIA does ? Sure so….
“If this survey had involved consumers actually purchasing diamonds, spread and apparent size would [but ain’t n.r.] have been a very important factor in the grade setting of this and some other stones.”

So what is a shopper to do with these ?
A readable companion to the GIA lab report sounds like a good idea, doesn’t it ?
User friendly as is, this article is no user guide. Is GIA preparing one?  Is it too early? A certain bit of the article sounds like a particularly good start. A certain table (on page 10) makes a rare invitation to ponder if and how those grades show anywhere but on the price tag. Thank you !  Finally a way to read through those intricacies at a glance. “At a glance” is way more democratic than a thick tome.

By all means, something that takes 5 seconds to read and 10 minutes to understand has a better chance to urge an open minded view over those precious grades.

For starters, it would be interesting to add one more line on the table for the cut grades and collect Pricescope wisdom into it. Something like this:

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

Ira (Ruffles have Ridges) Z.
____________

If you're looking for diamond shopping tips...this (along with this update) might do the trick!

however...caution: known to have been regarded as armed and dangerous…

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

it is always harder to find a "mind clean" stone than a eye clean stone.

Very interesting assessment, Garry.  Thanks for sharing it (and to Leonid).

A few notes, just reactions from my limited perspective:

From page 11:
"The findings of this GIA study, and other studies and approaches to cut grading, will fundamentally change industry expectations.  If part of the purpose of this GIA article is to change those preconceptions to match the findings of human observers and the realities of the laws of physics, why be considerate of preconceived trade customs and opinions? As Paul Slegers says, we should not be led by logic dictated by adages like “my child is beautiful”. This would lead to a lost opportunity to take full advantage of the laws of nature to maximise both the beauty and the yield on each and every one of those “finely crystallized carbon” creations.

Paul also notes that trade observers are educated in a certain way of looking, judging and thinking. No matter how ‘blind’ you make their observations by not giving them any parameters before judging, they can identify certain parameters and they may inevitably be influenced in their observational judgements. "

While I think I know what you are getting at, that the stones were being judged relative to the exisiting concept of ideal, but on some level changing the preconceptions of those involved in the study with the results of the same study sounds a bit circular in logic from the outset.

That said, that some people with "trade eyes" might be looking at a stone for isolated characterisitics and biasing the grading response without really looking at the visual performance seems to be an important failing.  Is there a breakout in the study of consumer preferences compared to professionals? 

There's still a lurking question of who the beholder of the beauty is, i.e. judging beauty presupposes some standard.

From page 12:
"Secondly, the GIA article mentioned that diamonds that exhibited excellent symmetry with Ideal-Scope or Hearts and Arrows viewers were not rated any higher by observers than those with lessor patterns. I suspect that their study only focused on diamonds within very good proportions, and in this respect, Peter Yantzer and I have never subscribed to the idea that Hearts and Arrows diamonds offer any better appearance to the naked eye than well cut diamonds with small symmetry deviations. Had GIA tested diamonds with the ideal-scope with the purpose that it is designed to be used for, rather than simply as a gauge of symmetry, I feel they would have discovered benefits form its usage and weaknesses in their current symmetry grading method.  "

Maybe explicitly stating "light leakage" versus optical symmetry would be clearer?  

I still wonder that symmetry isn't properly accounted for, as you point out.

From page 12:
"For instance diamonds that have painted or built up upper girdle facets like EightStar diamonds® were said to show “little..."

An honest question, do EightStars have painted facets?


- - -

Cat 5 does appear there only make sure that Cat 4 is better than something.

- - -

Maybe this belongs in a separate topic, but what would be the ultimate ultimate methodology and grading system?

OK, in for a penny, in for a pound.

Since I have no proper reputation to sully, here I go.  Thanks in advance for forgiving big mistakes.  I find the Pricescope info hangs together logically in a way that I feel like usually, with one thing pointing in a straight line to another, one idea flows pretty well to the next, and I am motivated to participate.  In the case of this response…I’m more going out on a limb.

In the case of this study you've reacted to, Garry, no, I've not read the original.  Hard enough time skimming yours.  Still, some reactions, and questions, I'll try to re-state here.

Regarding my last point above, and generally...your review is very "context dependent" upon the original piece.  So, it is a review...naturally.  You say right at the beginning: "(the categories) may not be the basis of the final grades. It seems their foundation is incomplete which means that this analysis of it must also be incomplete."  Relatedly, on your screen 10, where you present the chart of reported effects to light performance, you introduce it with this comment: "The GIA study noted during the observational survey that factors other than proportions played a role in diamond beauty. This table attempts to simplify those observations."  My hunch is simply that your intention in providing the details of the chart is to shoot down the paper tiger and intended suggestion that proportion data is not substantially sufficient to provide for cut grades.  The items in the chart do not seem substantive, and I was betting you were just trying to draw the items out, putting them in black & white.  Wrong?

My point on your comments on pricing and cut were just that...good stuff.  I recall reading similar or identical comments on this board before, presume they were for you, and bear repeating.

Finally...a "second" reaction to your piece, and the first point I tried to make above...really, this point is embedded in some fundamental questions I have about HCA and diamond cut grading generally.  First of all, allow my complete relative ignorance about crown & pavilion angle actual patterning in the real world.  Of course, without this knowledge, setting up schemes to measure them could be sharply criticized.  And yet, let's point out that your fundamental typology of BIC, TIC and FIC as describing the spectrum of ideal cuts has as one of them a class (FIC) that you describe as occurring as about 1 in 2000, wasn't it?  So...basic questions:

1) Given the classic graphical display represented coincident with the HCA report, where you get the big red pathway going from “Northwest to Southeast,” i.e., upper left to lower right, I suppose that your frequent cry to suggest the range of ideal cuts can be expanded is consistent with this broader big red valley…given this broad swath of red…why the more narrow option for AGS0 in their newer system…why not a bigger spectrum.  Also, and likewise…to what extent does that big red area map onto your own system of categorizing of 0 – 2…maybe the match is not that great.

2) Generally, if we allow that the big red area on the HCA presentation suggests good performance…and I do know that upper left portions and lower right portions do stake out the BIC and FIC typology…then it would seem a mistake to have poorer cut diamonds follow the track of this big red area, which is what at least GIA 1 – 3 seems to do.  So, maybe this doesn’t make any sense…and I’ll qualify it by pointing out that in the last month, people on the Pricescope board have queried about diamonds that are very clearly in the outlying blue areas of the chart at the upper right, suggesting some actual diamonds under consideration do exist out there…but my question is basically…wouldn’t it make more sense for poorer cut diamonds to follow a path perpendicular to the big red area on the HCA chart..or does this make no sense…perhaps representing no, or not many actual diamonds.  I’m intending to attach below a highly primitive mockup of us just such a chart.  And that’s my 2 cents for today.  Your indulgence is greatly appreciated.

Ira (Ruffles have Ridges) Z.
____________

If you're looking for diamond shopping tips...this (along with this update) might do the trick!

however...caution: known to have been regarded as armed and dangerous…

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

Date: 1/12/2005 2:45:52 AM
Author: lostdog
Re Paul from Antwerps comments about the trade observers being "preconditioned"
While I think I know what you are getting at, that the stones were being judged relative to the exisiting concept of ideal, but on some level changing the preconceptions of those involved in the study with the results of the same study sounds a bit circular in logic from the outset.

That said, that some people with 'trade eyes' might be looking at a stone for isolated characterisitics and biasing the grading response without really looking at the visual performance seems to be an important failing.  Is there a breakout in the study of consumer preferences compared to professionals? 

There's still a lurking question of who the beholder of the beauty is, i.e. judging beauty presupposes some standard.

Here is a link to one of my most ardent hate club fan leaders discovery of a diamond that in their opinion proved that the numbers are a bad predictor of diamond beauty. Now I agree that such a stone would, by its numbers, look very attractive - but the trade observers would easily have picked it as "wierd".  http://www.diamondtalk.com/forums/showthread.php?t=54913

I still wonder that symmetry isn't properly accounted for, as you point out. Yes - it is a problem that GIAmis aware of, but solving such a problem when you have 50 years of baggage is not so easy. As Einstein said "You can not solve problems with the same thinking that created it".  GIA have made attempts to bring people from outside the organisation and the industry to work on this project - but even that is not easy to pull off.

From page 12:
'For instance diamonds that have painted or built up upper girdle facets like EightStar diamonds® were said to show “little...'

An honest question, do EightStars have painted facets? Yes, of course they do


- - -

Cat 5 does appear there only make sure that Cat 4 is better than something.

- - -

Maybe this belongs in a separate topic, but what would be the ultimate ultimate methodology and grading system?
scan the diamond and build an excellent 3D model, then use physics and software to judge the diamonds beauty based on a range of basic light responses calibrated by humans. The greater benefit of such a system is that it can then be used to reverse engineer the design of truly beautiful diamonds - it can even lead to freestyle designs and one off pieces that follow the outline of the rough diamone yet still produse a beautiful diamond. Sergey Sivovolenko who designed DiamCalc and the worlds most advanced Sarin type scanners is the world leader in this field.

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

........... Karl has joined the diamond trade and is now posting as Karl_K

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Garry Holloway FGAA DipDT

HCA and Ideal-scope developer

http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian]

I will wait until final polish to judge the GIA system, but I agree with Dave that the fact that it’s being established is a step forward.

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

Ok.  Some cursory comments about the GH review:

1.  It should not be surprising that the 5th grade (assume it will be called “poor”) will not be seen on many reports.  After all, how often do we see graded diamonds with poor symmetry or polish?  Having a “throwaway” grade is to promote value for grades 1-4.

2.  Fluoro is prominent in the review as having “No effect on apparent  brightness and fire.”  Will this influence an adjustment to reduce or eliminate discounts for fluorescent goods?

3.  The barrage of new information could, for a time, make existing tools even smaller pieces of a larger overall puzzle.  For a RB diamond someone wishing to scrutinize to the “nth” degree could seek out…

Carat weight
Color, Clarity, Sym, Polish, Girdle, Culet (and the lab that did the grading)
AGS Cut Grade
GIA Cut Grade
AGA Cut Grade
Standard Sarin proportions
Minor facet Sarin proportions
Ideal Scope Image
Hearts & Arrows Image
HCA prediction
Virtual Modeling prediction
Ray Tracing, Angular Spectrum evaluation
BrillianceScope / Isee2 / Imagem prediction

That’s a lot of information.

Garry, thank you for the obvious time and effort you put into giving your perspective.

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

Date: 1/11/2005 7:456 PM
Author: Dancing Fire
GIA should forget about putting a cut grade on their cert ,just put all the specs and let the consumer decide by using their eyes,HCA,AGA,IS,B-scope,Isee2 etc,etc...

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

Date: 1/12/2005 72:22 AM
Author: valeria101

(3) Minor facets... well, I have no reason to disagree that at some point this added cut grading factor is splitting a very, very thin hair (the starin of H&A ideals that is). But, is it possible to improve the looks of a stone with so-so crown&pavilion match by modifying the minors ?  Jonatahan's page does not deal with this of course. It seemes that GIA does. Wrong ?

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

Garry characterizes these examples as a rarified area of diamond cut.  It’s true. The tolerances for “A Cut Above” major proportions are already tight, just as they are for 8*, Venus and H&A endorsed by Rhino and Robin&Todd.  Within this realm of already-tight proportions the minutiae we insist on for minor facet construction does not influence the degree of beauty so much as the character of the beauty.  We call it fine-tuning the visual balance.  The effects are noticeable to the most discerning, but the stones are all beautiful and noting differences would be splitting-hairs in the world of normal commercial grading.

Of course Strm, you are correct that those of us committed to precise physical symmetry are absorbed by the subtle differences in minor facet construction.  They create consistent performance within our established larger proportion combinations.  Having strict tolerances for all aspects of the stone, major and minor, is the way a brand acquires an identity:  Brian’s ACAs have a certain visual footprint, as do Paul’s Venus by Infinity, 8* etc.  Rhino has his favorite set of combinations that result in a footprint he’s studied and approved, as do R&T. 

In our case, Brian’s in-depth studies drive decisions on tolerances that imbue the brand with consistent performance and the balance we desire.  We have observed (as have others with reputable brands) that the performance of a true-patterned diamond with a known set of proportions is as consistent as any HCA prediction, but with an even greater level of detailed analysis.  Maybe HCA2.0 will build on some of this knowledge.

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007

Garry, I think the “commercial strategy” statement is unfair to Rhino. Truthfully it would be a lot easier for him to do away with the time-consuming efforts and sell low-standard, phony H&A stones using minimal imagery and limited consumer education.  His in-depth analysis is motivated by the same passion for understanding diamond beauty as yours or ours is.  I applaud him for contributing to the overall knowledge base here.  Brian Gavin and Paul Slegers are both in the business of working to understand and evolve diamond beauty.  Neither of them “overstates” what they observe for commercial strategy and I don’t believe Rhino does either.

Thus, I believe “overstates” is to Rhinoceros as “conjecture” is to Oz-man.
The Knight counter-conjectures that Oz-man “overstates” the following...

John

__________________________

John Pollard

Whiteflash Director of Education 2004-2007