2006 GIA grading report - Post info here please

[Garry H (Cut Nut)]

Dave it is still not quite that easy:

Perhaps as a result of the Darwinian survival of successful hunters, we have an instinctive ability to estimate the position of a deer running through a heavily wooded forest. Although we only see occasional glimpses of the deer, in our mind we see the deer almost continually. When you rock a diamond (see fig 7.) your mind may perceive sparkles from different areas of the gem as being the same continual rolling flash. At this link www.cutstudy.com/cut/english/grading1/4.htm you can play a virtual game that helps illustrate this concept.

I do not think direct light readings can overcome this

 

[oldminer]

Garry;

I don't want to be argumentative, but I don't get the deer analogy as being positive for any case you might be making. If one thinks they see the deer when it isn't really there, then their mind is playing tricks on them and their assessement of reality is distorted. We know that the eyes and the mind do play tricks on our perceptions, but machines have been designed to avoid those human failings.

If we seek accuracy and repeatability to our measures or grades, then we need to eliminate human frailty from the equation wherever possible.

How are you addressing the the location and type of inclusions present and how they may affect light behavior in the models?

How is the degree of transparency being addressed with repeatable accuracy. We don't even have such a scale of opacity for diamonds agreed upon, do we?

Does anyone admit that the measures taken do not totally address the exact shape of a given diamond in full? Are there measures that are not taken or ones taken which are not completely accurate?

 

[adamasgem]

Date: 1/9/2006 2:58:33 PM
Author: oldminer
If we seek accuracy and repeatability to our measures or grades, then we need to eliminate human frailty from the equation wherever possible.

How are you addressing the the location and type of inclusions present and how they may affect light behavior in the models?

How is the degree of transparency being addressed with repeatable accuracy. We don''t even have such a scale of opacity for diamonds agreed upon, do we?

Does anyone admit that the measures taken do not totally address the exact shape of a given diamond in full? Are there measures that are not taken or ones taken which are not completely accurate?

Both Dave and Garry make valid points, and unfortunately there is no one answer.

Machines can evaluate a genstone in a static or limited range of dynamic positions and one or morelimited lighting conditions, and they take into account the non linear internal absorption and inclusion characteristics of the particular, non idealized stone.

Modeling, if done correctly, using the most accurate measurements available, can eventually predict this behavior for a wider range of conditions, conditions that reflect both human perception and viewing conditions, and somehow generate a "metric" that relates to an overall performance rating.

Both methodologies can be complementary, or they can be mutually exclusive, if the "correct" selection of lighting conditions, for example, are not used, or in the case of modeling, someone stupidly idealizes the numbers by making an assymetric stone symmetric, and then, for convenience, changes the measured numbers to conform with their distorted perception of what they consider important quantization or rounding.. GIGO garbage in, garbage out..

Both methodologies suffer from "measurement" errors, but ANY methodology used should clearly define the assumptions and conditions used. That is what the current discussion is all about. I, and others, don''t agrree with distortion of measurement accuracy by arbitrary rounding.

Besides that, there are MANY OTHER issues regarding the conditions used to generate the "metric" which will take years to resolve, IMHO.

Instead of a step ahead in undestanding, I think some have taken two steps back..

The public should understand that whether you measure or predict, there are errors and ASSUMPTIONS that can greatly influence the "outcome" of the result. What result do you want,
I can build a machine that is tailored to a particular stone, or easier, develop a "mathematical" model that is tailored to generate the "best" metric for the same stone.

Both methodologies can be objective and "truthful", or either of them, or both, could be pure BS.

 

[JohnQuixote]

Facetware: Adjustments for rounding

Some time ago Strmrdr pointed out a depth adjustment necessary due to FW rounding, so I put these examples together for our staff (these were done with the old interface, but the results are the same with the new one).

Hopefully this will be useful info for anyone who will be using (or who's clients will be using) the software.

Example A: You may receive different grades depending on your rounding choice

Depth: 60.8
Table: 55
CA: 35
PA: 40.7
Star: 50
LH: 80
Girdle: Thin to Medium
Culet: N
Polish: Ex
Sym: Ex

In this example the diamond’s PA is 40.7. Your choice between 40.6 and 40.8 is the difference between VG and EX. Facetware awards EX when you choose to enter 40.6 (likely because the CA is high at 35.0 and 40.8 would make the diamond too steep for its tastes). Thus, two different grading implications can be produced for any diamond with these measurements.

Consider also that any diamond with a 34.8 or 34.9 CA average will be forced to 35 in FW, so you will be faced with the same choice in FW for any of these combined with 40.7.

 

[JohnQuixote]

The next 2 examples are near the border of ideal-shallow, showing how Facetware gives a VG rather than an EX result - not due to PA/CA combination, but for failing to adjust depth when forced to round (credit to Strm for first pointing this out a while back).

Example B: Depth adjustment for Pavilion Angle rounding

Depth: 59.9
Table: 56
CA: 34.4
PA: 40.5
Star: 50
LH: 80
Girdle: Thin to Medium
Culet: N
Polish: Ex
Sym: Ex

The Given PA is 40.5. Facetware forces a choice between 40.4 and 40.6 PA. For this example, select 40.6 rather than 40.4. The numbers result in VG (‘Predicted Grade for Diamond 1’ below) but not due to PA/CA combination. The problem is the PA was raised from 40.5 to 40.6 but there was no adjustment to overall depth when you made the diamond slightly deeper. Adjusting depth from 59.9 to 60.0 results in a grade of EX (‘Predicted Grade for Diamond 2’).

 

[JohnQuixote]

Example C: Depth Adjustment for Crown Angle Rounding

Depth: 60.3
Table: 55
CA: 34.3
PA: 40.6
Star: 50
LH: 80
Girdle: Thin to Medium
Culet: N
Polish: Ex
Sym: Ex

The CA average is 34.3. Facetware forces it to 34.5. Again, VG results (‘Predicted Grade for Diamond 1’) but not due to CA/PA. Here also, the problem is raising the diamond’s CA a full .2 degrees to 34.5 but not adjusting overall depth. Adjusting the 60.3 up to a 60.4 (or 60.5) results in a grade of EX (‘Predicted Grade for Diamond 2’).

 

[adamasgem]

Date: 1/9/2006 5:12:05 PM
Author: JohnQuixote

Example C: Depth Adjustment for Crown Angle Rounding

Depth: 60.3
Table: 55
CA: 34.3
PA: 40.6
Star: 50
LH: 80
Girdle: Thin to Medium
Culet: N
Polish: Ex
Sym: Ex

The CA average is 34.3. Facetware forces it to 34.5. Again, VG results (‘Predicted Grade for Diamond 1’) but not due to CA/PA. Here also, the problem is raising the diamond’s CA a full .2 degrees to 34.5 but not adjusting overall depth. Adjusting the 60.3 up to a 60.4 (or 60.5) results in a grade of EX (‘Predicted Grade for Diamond 2’).

John
Good examples of the total lack of mathematical consistency in GIA's software.. Did you note that, in your example C, where you changed the depth % by 0.1% the girdle thickness changed by 0.5%... I take it that Girdle thickness floats?

I haven't bothered to download it, because they probably have a special trap in there for me

What do you expect for $10million plus of industry money, grammer school perfection?

I'm sure they will add a special industry convenience button where you select the final grade you want and they'll adjust the numbers to get it..

 

[JohnQuixote]

Date: 1/9/2006 5:34:17 PM
Author: adamasgem

Date: 1/9/2006 5:12:05 PM
Author: JohnQuixote

Example C: Depth Adjustment for Crown Angle Rounding

Depth: 60.3
Table: 55
CA: 34.3
PA: 40.6
Star: 50
LH: 80
Girdle: Thin to Medium
Culet: N
Polish: Ex
Sym: Ex

The CA average is 34.3. Facetware forces it to 34.5. Again, VG results (‘Predicted Grade for Diamond 1’) but not due to CA/PA. Here also, the problem is raising the diamond’s CA a full .2 degrees to 34.5 but not adjusting overall depth. Adjusting the 60.3 up to a 60.4 (or 60.5) results in a grade of EX (‘Predicted Grade for Diamond 2’).

John
Good examples of the total lack of mathematical consistency in GIA's software.. Did you note that, in your example C, where you changed the depth % by 0.1% the girdle thickness changed by 0.5%... I take it that Girdle thickness floats?

I haven't bothered to download it, because they probably have a special trap in there for me

This was done in the old interface. I made only the Thin-Medium pulldown entries. Girdle% did float as a result of the depth increase. The new interface allows you to select manual depth and girdle entries.

I'd like to know what's used as bait in a Marty-Trap.

 

[adamasgem]

RE: I''d like to know what''s used as bait in a Marty-Trap.

Well, John, I''m extremely partial to female blonds

Seriously, what GIA needs to do first, and they stupidly, (for lack of a better word), didn''t do, is to allow the input of the actual numbers generated from whatever measurement device one is using, the more accuracy the better, and then interpolate internally in their software, to whatever granularity they have in their hyped "database". If the variance about the means are known, then that could also be input, and a weighted interpolation be done. Case closed..

Remember my words, as that is probably what is going to happen.. eventually..but given the inertia over there, it might take ten years

Then we can get down discuss the reality of the models and envirionments used to generate the "database". A much more interesting discussion..

 

[Garry H (Cut Nut)]

Date: 1/9/2006 2:58:33 PM
Author: oldminer
Garry;

I don''t want to be argumentative, but I don''t get the deer analogy as being positive for any case you might be making. If one thinks they see the deer when it isn''t really there, then their mind is playing tricks on them and their assessement of reality is distorted. We know that the eyes and the mind do play tricks on our perceptions, but machines have been designed to avoid those human failings.

If we seek accuracy and repeatability to our measures or grades, then we need to eliminate human frailty from the equation wherever possible.

It is the human part that machines can not yet do Dave

Sergey has worked out a way to teach them to do it (using ETAS).
It is not easy, but we believe it is possible.

 

[adamasgem]

Date: 1/9/2006 11:37:03 PM
Author: Garry H (Cut Nut)

Date: 1/9/2006 2:58:33 PM
Author: oldminer
Garry;

I don''t want to be argumentative, but I don''t get the deer analogy as being positive for any case you might be making. If one thinks they see the deer when it isn''t really there, then their mind is playing tricks on them and their assessement of reality is distorted. We know that the eyes and the mind do play tricks on our perceptions, but machines have been designed to avoid those human failings.

If we seek accuracy and repeatability to our measures or grades, then we need to eliminate human frailty from the equation wherever possible.

It is the human part that machines can not yet do Dave

Sergey has worked out a way to teach them to do it (using ETAS).
It is not easy, but we believe it is possible.

Dave: I believe what Garry is saying is true, if anyone can do it, it is probably Sergey..
BTW Garry, neat illustration thanks to Sergey..

 

[RockDoc]

A lot of interesting stuff here, but there is a very simple solution to all of this.

For those that don''t want to rely on disclaimers, restrictions, potential inaccurate reports, etc. then it is in the hands and "wallets" of the consumers.

Simply don''t accept the new reports and stick with AGSLAB.

I am not going to say that AGS''S methods are completely "done" yet, but they are certainly on the right track.

So if consumers want more accuracy and potentially less affect from ROUNDING UP, and conclusions made that don''t report the level of certainty, then accept the report that doesn''t have those conditions and limitations to it.

Now see wasn''t that simple?

Rockdoc

 

[Garry H (Cut Nut)]

Hard to disagree with you Roc.
It is funny - the 2nd tier labs have always given us rounded % data (although IGI is now giving abgles too i am pleased to say

).

The good thing is that this rounded data can still be used for rejection purposes by savy consumers. I hope it leads to more information usage by treaders.

For instance many B2B sights list things like table size, total depth, girdle thickness and culet - but this info is no longer actually written anywhere where a trained monkey data entry person can easily find it without making terrible goof-ups.
So I wonder what all the b2B listing houses will do?
Perhaps they will all start to list important things like crown and pavilion angles instead of useless real-estate wasting data like culet size (which probably knocks out 2% or less of all stones).

Take total depth % as another bit of useless data - two diamonds with the same diameter, table size and total depth % can vary by as much as 10% in carat weight and still have the same girdle thickness and culet size (more than 10% weight variance is posssible if the girdle thickness is also variable).

 

[Paul-Antwerp]

Date: 1/10/2006 1:42:25 AM
Author: Garry H (Cut Nut)
For instance many B2B sights list things like table size, total depth, girdle thickness and culet - but this info is no longer actually written anywhere where a trained monkey data entry person can easily find it without making terrible goof-ups.
So I wonder what all the b2B listing houses will do?
Perhaps they will all start to list important things like crown and pavilion angles instead of useless real-estate wasting data like culet size (which probably knocks out 2% or less of all stones).

Take total depth % as another bit of useless data - two diamonds with the same diameter, table size and total depth % can vary by as much as 10% in carat weight and still have the same girdle thickness and culet size (more than 10% weight variance is posssible if the girdle thickness is also variable).

Heheh. That will indeed be interesting to see, how all the virtual lists will adapt to this.

Live long,

 

[valeria101]

Date: 1/10/2006 11:36:08 AM
Author: Paul-Antwerp

Date: 1/10/2006 1:42:25 AM
Author: Garry H (Cut Nut)

Perhaps they will all start to list important things like crown and pavilion angles instead of useless real-estate wasting data ...

Heheh. That will indeed be interesting to see, how all the virtual lists will adapt to this.

What happened with the AGS reports? Could that be a precedent?

I''ve always wondered why the ''extras'' on AGS and EGL paper were not listed here, until the (small) ''In House'' database turned up.

 

[JohnQuixote]

A little bit of devil's advocate, fellows (and fellettes):

Setting aside the Facetware problems for a moment, I don't think we should knock GIA just for wanting to allow a broader range of taste in their top grade than AGS does.

For the majority of consumers in the pedestrian world GIA EX will be a better assurance of quality than they have had in the past, as it protects a buyer with regard to depth/spread, durability, polish & symmetry. It also reflects a cut quality that is well above average: In the real world, the vast number of diamonds sold without paper - or sent for grading by softer labs - far outweighs the number that will be graded by GIA or AGS. AGS Ideal may represent the very top of the global cut pyramid. GIA EX encompasses that range and then some (allowing for some configurations farther away from Tolkowsky - not necessarily a bad thing). Just because it does not meet the strict paradigms many of us here have personally embraced does not make it bad - it is still a quality assurance well above average.

Marty has voiced - and I agree - that a broad top grade (without acknowledgment for super-elite) fails to reward the cutters and craftsmen producing the most premium diamonds... That's not new. Even AGS Ideal does not identify what some cite as 'superideal'... And that brings us back to different matters of taste among equally well-performing premium diamonds. We can discuss these things all day, but in the pedestrian world the number of people who know about (or care about) such details pales next the those who just want a beautiful diamond.

Selfishly, I agree with Rockdoc. We few (we happy few)

who WANT all the bells and whistles and accurate measurements will send to AGS. In the larger picture of the real world the development of the new GIA grade is a positive development for consumers.

 

[JohnQuixote]

Back to Facetware: I think Marty''s suggestion for GIA to allow EXACT measuements (not rounded) to be placed on their grading documents is very sound. They could still interpoloate those numbers however they like within their metric for a grade.

As it stands, the GIA grading report measurements are far weaker in accuracy than a Sarin scan.

 

[strmrdr]

Date: 1/10/2006 12:36:23 PM
Author: JohnQuixote
Back to Facetware: I think Marty''s suggestion for GIA to allow EXACT measuements (not rounded) to be placed on their grading documents is very sound. They could still interpoloate those numbers however they like within their metric for a grade.


As it stands, the GIA grading report measurements are far weaker in accuracy than a Sarin scan.

Which in my opinion are far too inaccurate to start with.
Whats interesting is rounding bites the sarin also if you want to get that deep.
they are rounded to the nearest .1 then averaged which can bring in a greater error.
This didnt come to light until I stared looking at helium scans vs max accuracy setting on the sarin scans.
This came up on the forum the other day when the sarin average hit 41 and the ags cert and the helium said 40.9 and 40.94 repectable.
This was enough to add a lot of points to the hca score.
looking at all the pavilion facet angles if you rounded up the helium angles they would have been the same as the sarin angles.
little OT but interesting when we are talking about using measurements and scores.

 

[adamasgem]

Date: 1/10/2006 2:09:21 PM
Author: strmrdr

Which in my opinion are far too inaccurate to start with.
Whats interesting is rounding bites the sarin also if you want to get that deep.
they are rounded to the nearest .1 then averaged which can bring in a greater error.
This didnt come to light until I stared looking at helium scans vs max accuracy setting on the sarin scans.
This came up on the forum the other day when the sarin average hit 41 and the ags cert and the helium said 40.9 and 40.94 repectable.
This was enough to add a lot of points to the hca score.
looking at all the pavilion facet angles if you rounded up the helium angles they would have been the same as the sarin angles.
little OT but interesting when we are talking about using measurements and scores.

I''ve seen some comparisons between machines from different vendors, and it is reported by people I trust that the Helium is more accurate than the Sarin. What s interesting in your comment is the issue of the difference in the HCA score (which I believe is based on MSU data) between 41.0 and 40.9, which sort of points out that inaccurate measurements, whether produded by machine inaccuracies or arbitrary ROUNDING, might well give misleading results.

GIA''s own contour maps in their original brilliance article show the vast differences in sensitivity to WLR versus pavilion angle with differing combinations of crown angle, etc. Why they went to their rounding scheme is beyond me.

 

[valeria101]

Date: 1/10/2006 3:50:02 PM
Author: adamasgem


Why they went to their rounding scheme is beyond me.

.... to force interested clients to demand better precision and save the effort to push for it from the start ?

GIA''s cut grades have been brewing for so long, it must have been a huge and tremendously expensive political process

 

[Paul-Antwerp]

Date: 1/10/2006 12:32:51 PM
Author: JohnQuixote
A little bit of devil''s advocate, fellows (and fellettes):

Setting aside the Facetware problems for a moment, I don''t think we should knock GIA just for wanting to allow a broader range of taste in their top grade than AGS does.

For the majority of consumers in the pedestrian world GIA EX will be a better assurance of quality than they have had in the past, as it protects a buyer with regard to depth/spread, durability, polish & symmetry. It also reflects a cut quality that is well above average: In the real world, the vast number of diamonds sold without paper - or sent for grading by softer labs - far outweighs the number that will be graded by GIA or AGS. AGS Ideal may represent the very top of the global cut pyramid. GIA EX encompasses that range and then some (allowing for some configurations farther away from Tolkowsky - not necessarily a bad thing). Just because it does not meet the strict paradigms many of us here have personally embraced does not make it bad - it is still a quality assurance well above average.

For the second consecutive day, I beg to disagree with you, John. And this time, I have clearly re-read your post. Although, I wonder about that devil''s advocate-part

Especially when you say GIA-EX will be a better assurance of quality than in the past, I fear that you are wrong. The average cutter, aiming to cut for a GIA-report, will be naturally inclined to go for the heaviest possible GIA-EX, and the Sarin-software will assist him in this. Remember, these are cutters, who mostly do not have the sophistication in judging cut that we have, and they will rely heavily on Sarin in choosing their proportion-sets.

In stead of improving their cut-quality, they will bring it down, by cutting a very high number of steep-deep GIA-EX''s. Where they had the difficulty before of getting EX-EX on polish and symmetry, now, in order to get EX on the overall cut-grade, VG suffices on polish and symmetry.

So, the cutter wins a few % in extra weight, he can be more sloppy in polish and symmetry, and he is awarded with a grading-report, that includes a new feature, its cut-grade, which might even be a reason to sell it for more than a stone with an old GIA-report.

A fast-food-restaurant also has a great quality-assurance.

Live long,

 

[adamasgem]

Date: 1/10/2006 4:03:45 PM
Author: valeria101

Date: 1/10/2006 3:50:02 PM
Author: adamasgem


Why they went to their rounding scheme is beyond me.

.... to force interested clients to demand better precision and save the effort to push for it from the start ?

GIA''s cut grades have been brewing for so long, it must have been a huge and tremendously expensive political process

Yup.. The tail wagging the dog.. Looser grades ---> More paper sold ------> Higher Salaries and Bonuses for the "priviledged" few

Political process is an understatement...

 

[strmrdr]

Date: 1/10/2006 5:22:31 PM
Author: adamasgem

Date: 1/10/2006 4:03:45 PM

Author: valeria101

Date: 1/10/2006 3:50:02 PM

Author: adamasgem



Why they went to their rounding scheme is beyond me.

.... to force interested clients to demand better precision and save the effort to push for it from the start ?

GIA''s cut grades have been brewing for so long, it must have been a huge and tremendously expensive political process

Yup.. The tail wagging the dog.. Looser grades ---> More paper sold ------> Higher Salaries and Bonuses for the ''priviledged'' few


Political process is an understatement...

yep.
A lot of consumers have a misconception that the labs work for consumers.
They work for the sellers and are not an independant opinion on the diamonds grade and guarentee nothing.

They get too harsh and the industry will just find someone else to grade the diamonds with lower standards.

Right now ags has a nice niche market for themselves as graders for top cut diamonds so they can afford to be harsh because the market premium lets them.

 

[strmrdr]

Date: 1/10/2006 3:50:02 PM
Author: adamasgem

I''ve seen some comparisons between machines from different vendors, and it is reported by people I trust that the Helium is more accurate than the Sarin. What s interesting in your comment is the issue of the difference in the HCA score (which I believe is based on MSU data) between 41.0 and 40.9, which sort of points out that inaccurate measurements, whether produded by machine inaccuracies or arbitrary ROUNDING, might well give misleading results.


GIA''s own contour maps in their original brilliance article show the vast differences in sensitivity to WLR versus pavilion angle with differing combinations of crown angle, etc. Why they went to their rounding scheme is beyond me.

I did a real bad job of explaining what I was talking about and I dont want to take this thread off topic.
You hit my main point when you said:
"points out that inaccurate measurements, whether produded by machine inaccuracies or arbitrary ROUNDING, might well give misleading results."

From gia''s point of view they cant do much about any rounding the machines may do other than use the most accurate scanner they can but to add on to that error with gross rounding is something I just dont get.

 

[Garry H (Cut Nut)]

Date: 1/10/2006 4:46:56 PM
Author: Paul-Antwerp
For the second consecutive day, I beg to disagree with you, John. And this time, I have clearly re-read your post. Although, I wonder about that devil''s advocate-part

Especially when you say GIA-EX will be a better assurance of quality than in the past, I fear that you are wrong. The average cutter, aiming to cut for a GIA-report, will be naturally inclined to go for the heaviest possible GIA-EX, and the Sarin-software will assist him in this. Remember, these are cutters, who mostly do not have the sophistication in judging cut that we have, and they will rely heavily on Sarin in choosing their proportion-sets.

Live long,

I am afraid I agree too Paul. As we know there are many very well equipped manufacturers who can cut angles with more precision than their Sarin Ogi scanners can report. Why would they cut for beuty and not for $ return? Thier families and shareholders and staff and competitors all provide valid pressure to go for the best financial return.

Now unlike Marty, I do not believe GIA are inherently bad or evil. I do not believe there is a "conspiracy" per se''.

I have been trying to understand their ''mistakes'' and it seems there are a few.

They did not stop people in the street - which unfortunately leads to a very broad spectrum of preferences - many of which may be flawed.
They interviewed mainly diamontaires and people looked with the lighting box at various diamonds.

I think the biggest issue is the old thing that I first noticed many many years ago - that lots of old timers do all their looking at diamonds with a loupe and back lighting. It is the same thing that I never got thru Brad''s thick head.

The primary lighting environment for commercial diamond traders is a desk mounted twin fluorescent lamp. The lamp is positioned so that light enters the pavilion making the location of inclusions easier; in this lighting the leakage we see in ‘steep & deep’ diamonds makes them appear very bright. Conversely many dealers do not like shallower diamonds that have less leakage appear relatively dark through a loupe in this environment. In addition the dealers head and loupe obstruct light sources from the front of the stone, so shallow stones appear very dark.

 

[RockDoc]

Hi All,

Knowing that "most mindsets" of the typical diamond cutters and their employers, the goal was to get the most weight from the piece of rough as possible. Painting and digging is only the "tip of the iceberg".

There are just tons of little geometrically driven "tricks" to get more weight which is a magic to a diamond cutters ears than is published on the internet, and virtually unknown to many gemologists. GIA doesn't totally and throughly disclose this information in their course studies.

Those who are in the business without gemological credentials, even know less. They look at stones with the methodology and approach that Garry defined.

I have met VERY FEW diamond industry guys who are really skilled at using a loupe to the degree of accuracy that gemologists would use a microscope. As for retail jewelers, most have "toy" scopes that impress shoppers, but are about as accurate and reliable as the proverbial mammaries on a bull.

Then a consumer walks in a store and is handed just a loupe, to assess the stone he is considering buying, and many times that stone is set in a ring, which also hampers the characteristics of a stone.


Paul Antwerp has provided a very accurate approach which is commonly at the forefront of what most diamond cutters do and react to.

While some want to take it "easy" on GIA, the fact remains that what they teach isn't disclosed on the reports they issue. I find this a rather strange double standard. GIA has been producing their grading reports for at least 30 years, leaving vast undisclosed information upon which consumers rely on to judge the quality of the diamonds they are buying.

While I must agree that our friend Marty Haske has been a bit harsh in his words and highly critical, he hasn't sugar coated the issue at all. Why after at least 30 years is GIA finally disclosing cut grade information, when during the same period of time it taught cut grading to the students taking the clasess to become Gemologists? I will yield that the curiculum taught still wasn't as technical and complete as the information brought to the consumers attention by Marty,Garry, myself,and some others who have been talking about what we've gradually learned in practice, that was left out of our coursework and studies.

I wonder if AGS hadn't opened a lab of its own, and there was no lab that disclosed cut gradings, would GIA be releasing a cut grade system now? Actually they did come up with a "weak" 4 grade system, but that system was never insitituted in their reports.

Was it deliberate? Was it intentional? Was this meant and driven by political or financial issues?

I believe it WAS NOT THE INTENT of Robert Shipley (the founder of both GIA and AGS). But over the years, we've arrived at the crossroads, of perhaps choosing to only accept the grading standards of one who provides and delivers a better defined cut grading system.

I do think we need ONE standard of grading that ALL the labs follow, IMHO as I genuinely believe that would be far better for both the industry and consumers as well.

Rockdoc

 

[adamasgem]

Date: 1/10/2006 8:20:43 PM
Author: RockDoc
Hi All,


While I must agree that our friend Marty Haske has been a bit harsh in his words and highly critical, he hasn't sugar coated the issue at all.

Moi?? Me?? Harsh and highly critical... thirty lashes with a wet noodle for even thinking that I could be like that..

What's sugar coating????

Now, I have been justly accused of having a lack of political awareness...

 

[adamasgem]

Date: 1/10/2006 7:20:58 PM
Author: Garry H (Cut Nut)

Now unlike Marty, I do not believe GIA are inherently bad or evil. I do not believe there is a ''conspiracy'' per se''.

Garry, please don''t put words in my mouth. While I might agree with you that some in their management might be "bad or evil" , but certainly it doesn''t apply to the vast majority of their hard working, and generally underpaid people (from what I understand). They have done a lot of good work (and some really bad also). They are NOT G-D, they are human, therefore they don''t deserve to be placed on such a high pedestal that some put them on, and they put themselves on.

 

[Garry H (Cut Nut)]

Sorry Marty - it was meant to be ''tongue in cheek''

but on re reading it - it does not come out that way.
Sorry Mate

 

[Paul-Antwerp]

Date: 1/10/2006 7:20:58 PM
Author: Garry H (Cut Nut)

I have been trying to understand their ''mistakes'' and it seems there are a few.

They did not stop people in the street - which unfortunately leads to a very broad spectrum of preferences - many of which may be flawed.
They interviewed mainly diamontaires and people looked with the lighting box at various diamonds.

I think the biggest issue is the old thing that I first noticed many many years ago - that lots of old timers do all their looking at diamonds with a loupe and back lighting.

The primary lighting environment for commercial diamond traders is a desk mounted twin fluorescent lamp. The lamp is positioned so that light enters the pavilion making the location of inclusions easier; in this lighting the leakage we see in ‘steep & deep’ diamonds makes them appear very bright. Conversely many dealers do not like shallower diamonds that have less leakage appear relatively dark through a loupe in this environment. In addition the dealers head and loupe obstruct light sources from the front of the stone, so shallow stones appear very dark.

You are more than absolutely right.

Weekly, I still meet dinosaurs here, old-timer well-established diamond cutters, who claim that a H&A is an ugly piece of round, which is essentially black-looking. No wonder if you are always judging cut with a strong light source behind the stone.

But then again, I read something really nice last mont: ''In business, it is not the big who beat the small, it is the fast who beat the slow''.

Live long,