GIA misgrading stones with strong fluor?

[stebbo]

Date: 9/19/2007 2:00:07 AM
Author: adamasgem

Do we ''see'' a lot of VSB''s on the market, I think they are snapped up by the chains, like DI, the Jewelry Exchange, and the like before they get to the wholesale lists.

No data obtainable there, half their stones don''t even list color or clarity, but yes, I can see them shopping by price alone.

And speaking of ''D''s''. I did an availability study awhile back which I posted on PS. Surprizing the distributional stats between labs on percentage of ''D''s'' graded. How many very good ''E''s have you seen, fluor or not?

I''m not even sure I can believe there''s such a thing as a good ''E'' - or a good any color given the inaccuracies in grading, human or machine. But I understand what you''re implying...

Try to find a 1/3 RBC that is VSB with a GIA dossier. Difficult. Been building a set for a potential court case to show a jury.

Here''s one - Hope he''s still available for you and not overkill.

 

[elmo]

Date: 9/19/2007 2:00:07 AM
Author: adamasgem
Try to find a 1/3 RBC that is VSB with a GIA dossier. Difficult.

I find this ironic (pointing someone in the trade to a consumer site), but try the BN search engine - there are 8 GIA VSB rounds there D-I under a half carat.

Something anecdotal, but it seems like I've seen relatively fewer AGSL reports with medium and higher. Admittedly a very small sample size here. But if one tier 1 lab was penalizing color with fluoro relative to another, wouldn't the other lab be grading more of the fluorescent stones?

Edit - looks like Stebbo and me were posting at the same time

.

 

[Garry H (Cut Nut)]

Date: 9/19/2007 1:50:17 AM
Author: Garry H (Cut Nut)
Question for the gathered gliterate''

We know that as size increases that the effect of a little color becomes greater.
We also know that as ray path gets longer (eg radiant) that face up color becomes more distinct.

Does fluoro play out the same way in both the above cases?

Bump

 

[stebbo]

Date: 9/19/2007 4:31:20 AM
Author: DiaGem
I have witnessed the GIA go from being lenient on fluo. high colored Diamonds back about two ago to being severely strict on the same type of goods in the last year or so.

I have seen GIA''s upgrading Fluo. high colored Diamonds back then. (for example H color with SB graded as G and even F''s)

And these days the GIA are down-grading Fluo. high colored Diamonds. (for example E-F''s with SB graded G and even H''s)

Something systematically happened in the last year or two switching up-grades to down-grades!!!

Could have been Marty''s spell?

I give up... total chaos.

GIA observation tests found people preferred fluorescence, so do many here of high repute. The effect is only positive unless the UV in our average environment is weaker than the grading chamber, yet they still sell at a discount. Bargains never last this long. What is stopping demand adjusting prices?

 

[stebbo]

Date: 9/19/2007 7:52:44 AM
Author: elmo
But if one tier 1 lab was penalizing color with fluoro relative to another, wouldn''t the other lab be grading more of the fluorescent stones?

Exactly, although is one lab penalizing or the other one rewarding?

So you''ve got a strong blue that''s shaping up to be an AGS-0 - do you send it to AGS and get your AGS-0 and associated premium, or off to GIA or EGL to get your color premium?

 

[strmrdr]

Date: 9/19/2007 8:16:42 AM
Author: stebbo

Date: 9/19/2007 7:52:44 AM
Author: elmo
But if one tier 1 lab was penalizing color with fluoro relative to another, wouldn''t the other lab be grading more of the fluorescent stones?

Exactly, although is one lab penalizing or the other one rewarding?

So you''ve got a strong blue that''s shaping up to be an AGS-0 - do you send it to AGS and get your AGS-0 and associated premium, or off to GIA or EGL to get your color premium?

Problem with that is that for example WF, Brian wont let SB/VSB into his ACA line.
If a cutter has a choice of rough he is going to spend extra time and weight loss on why would he pick some he has too sell at a discount if he has a choice?
If you look at GOG Classic line with GIA reports you will also see very few with anything above med.
Rather than a lab issue I think that most ags0 being med or lower would be a return on investment issue.

 

[adamasgem]

Date: 9/19/2007 7:50:05 AM
Author: stebbo

Date: 9/19/2007 2:00:07 AM
Author: adamasgem

Try to find a 1/3 RBC that is VSB with a GIA dossier. Difficult. Been building a set for a potential court case to show a jury.

Here''s one - Hope he''s still available for you and not overkill.

Stebbo, Thanks, I hadn''t looked in awhile.

That is an interesting stone (D/IF) if I had a spare $1300 (a little over my budget) to only stick it in the safe as an exemplar.

My WAG is that the true color is probably in the F/G range...

I actually did a search on a wholesale list for GIA papered RBCs and found two G-VSB''s which I''d prefer, (I buy at wholesale), as one of the things I wanted to do is build a "color" set to compare with my 17 masters I use for SAS2000 calibration.

I only have a D-strong, an F strong and an E-medium as exemplars (other than the rough cubes I use as fluor refs) which I bought a while back..

 

[stebbo]

Date: 9/18/2007 5:20:26 PM
Author: Richard Sherwood
Thanks Dave. I like how you adjusted the whiteness to show a true comparison between the indoor/outdoor lighting photos.

Man, I love that indirect daylight shot.

It''s interesting also to see EGL-Antwerp''s opinion of ''slight luminescence'', eh?

Was ''luminescence'' a term they used to use instead of ''fluorescence''? Maybe the diamond was phosphorescent under normal lighting conditions too?

 

[adamasgem]

Date: 9/19/2007 8:06:30 AM
Author: Garry H (Cut Nut)

Date: 9/19/2007 1:50:17 AM
Author: Garry H (Cut Nut)
Question for the gathered gliterate''

We know that as size increases that the effect of a little color becomes greater.
We also know that as ray path gets longer (eg radiant) that face up color becomes more distinct.

Does fluoro play out the same way in both the above cases?

Bump

Garry, I''m not sure of the correct answer, but fluor effects the apparent transmission characteristics, such tht there is more "trnsmittance" in the blue region, and therefore less absorption.

Remember, for the same "color grade" a larger stone has less nitrogen or absorption per unit pathlength anyway...

 

[Garry H (Cut Nut)]

Date: 9/19/2007 9:55:18 PM
Author: adamasgem

Date: 9/19/2007 8:06:30 AM
Author: Garry H (Cut Nut)

Date: 9/19/2007 1:50:17 AM
Author: Garry H (Cut Nut)
Question for the gathered gliterate''

We know that as size increases that the effect of a little color becomes greater.
We also know that as ray path gets longer (eg radiant) that face up color becomes more distinct.

Does fluoro play out the same way in both the above cases?

Bump

Garry, I''m not sure of the correct answer, but fluor effects the apparent transmission characteristics, such tht there is more ''trnsmittance'' in the blue region, and therefore less absorption.

Remember, for the same ''color grade'' a larger stone has less nitrogen or absorption per unit pathlength anyway...

Hmmm,,,
I kinda intuitively feel that Fluoro would not be as size dependant as the other factors Marty.
(it is a kind of intuitive scientific feeling type of analytic tool I have)

If I am more or less right then it has implications for the size related impact of fluoro on color (maybe?)

Maybe?

 

[adamasgem]

Date: 9/19/2007 10:04:40 PM
Author: Garry H (Cut Nut)

Date: 9/19/2007 9:55:18 PM
Author: adamasgem

Date: 9/19/2007 8:06:30 AM
Author: Garry H (Cut Nut)

Date: 9/19/2007 1:50:17 AM
Author: Garry H (Cut Nut)
Question for the gathered gliterate''

We know that as size increases that the effect of a little color becomes greater.
We also know that as ray path gets longer (eg radiant) that face up color becomes more distinct.

Does fluoro play out the same way in both the above cases?

Bump

Garry, I''m not sure of the correct answer, but fluor effects the apparent transmission characteristics, such tht there is more ''trnsmittance'' in the blue region, and therefore less absorption.

Remember, for the same ''color grade'' a larger stone has less nitrogen or absorption per unit pathlength anyway...

Hmmm,,,
I kinda intuitively feel that Fluoro would not be as size dependant as the other factors Marty.
(it is a kind of intuitive scientific feeling type of analytic tool I have)

If I am more or less right then it has implications for the size related impact of fluoro on color (maybe?)

Maybe?

Garry.. Perceived blue fluor is, as I understand it:
1) A function of the unquenched N3 aggrgates per unit volune
2) Proportional to the amount (and type) of UV pumped into the stone

Now, you also have the nonlinear human response to the stimulous to consider, are you looking at a pinpoint or a 100 watt light..

 

[angeline]

So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?

The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.

Thanks!

a

 

[strmrdr]

Date: 9/20/2007 7:29:34 PM
Author: angeline
So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?

The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.

Thanks!

a

worried about the color?
Have Brian, Bob or John grade it for you under no UV lighting.

 

[angeline]

Date: 9/20/2007 7:43:37 PM
Author: strmrdr

Date: 9/20/2007 7:29:34 PM

Author: angeline

So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?


The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.


Thanks!


a

worried about the color?

Have Brian, Bob or John grade it for you under no UV lighting.

Thanks storm, replied on the other thread

 

[stebbo]

Date: 9/20/2007 7:29:34 PM
Author: angeline
So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?


The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.


Thanks!


a

From what Marty was suggesting above with the GIA, that E has probably already factored in fluorescence, otherwise they would have bumped it to a D.

 

[stebbo]

Date: 9/20/2007 3:20:26 PM
Author: adamasgem

Garry.. Perceived blue fluor is, as I understand it:

1) A function of the unquenched N3 aggregates per unit volume

2) Proportional to the amount (and type) of UV pumped into the stone

Now, you also have the nonlinear human response to the stimulus to consider, are you looking at a pinpoint or a 100 watt light..

Very thought provoking...

Here''s one of them:

So you''ve got these UV frequencies coming in, bouncing around exciting these nitrogen atoms. As the refractive index at UV frequencies (and absorption co-efficients) differs to the small range in white light, maybe, just maybe, there''s a connection between the amount of fluorescence and proportions. A 34/42 for example might have very little UV leakage, maximum photon absorption, maximum fluorescence.

Another one:

Like size, it too would be a freak of nature if SB fluor caused the same shift in color in a K as an E. Too many non-linearities and in-dependencies.

 

[WorkingHardforSmallRewards]

Date: 9/19/2007 1:06:51 PM
Author: adamasgem

Date: 9/19/2007 7:50:05 AM

Author: stebbo

Date: 9/19/2007 2:00:07 AM

Author: adamasgem

Try to find a 1/3 RBC that is VSB with a GIA dossier. Difficult. Been building a set for a potential court case to show a jury.

Here''s one - Hope he''s still available for you and not overkill.

Stebbo, Thanks, I hadn''t looked in awhile.


That is an interesting stone (D/IF) if I had a spare $1300 (a little over my budget) to only stick it in the safe as an exemplar.



My WAG is that the true color is probably in the F/G range...


I actually did a search on a wholesale list for GIA papered RBCs and found two G-VSB''s which I''d prefer, (I buy at wholesale), as one of the things I wanted to do is build a ''color'' set to compare with my 17 masters I use for SAS2000 calibration.


I only have a D-strong, an F strong and an E-medium as exemplars (other than the rough cubes I use as fluor refs) which I bought a while back..

well, they do have a 30 day return period. You could always buy it telling them you were considering your options. then get 3 independent appraisals done, maybe only designed so as to identify the stone and specifically identify the color under non UV lighting. Then you would at least have a copy of a cert with a cert number and several reports citing the D grade as well as there non-UV grade. And then if it came back negative you could always send the certs to BN and share your findings with them, tell them you will send the stone back because they grading is inaccurate, and then who knows, maybe they will give you a discount

 

[adamasgem]

Date: 9/20/2007 7:29:34 PM
Author: angeline
So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?

The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.

Thanks!

a

The answer, in my opinion, is yes...

 

[adamasgem]

Date: 9/20/2007 10:17:47 PM
Author: stebbo

Date: 9/20/2007 7:29:34 PM
Author: angeline
So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?


The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.


Thanks!


a

From what Marty was suggesting above with the GIA, that E has probably already factored in fluorescence, otherwise they would have bumped it to a D.

No, you are misinterpreting, that "E", might be a true "F"

 

[angeline]

Date: 9/20/2007 11:19:07 PM
Author: adamasgem

Date: 9/20/2007 10:17:47 PM

Author: stebbo

Date: 9/20/2007 7:29:34 PM

Author: angeline

So um bringing ths back to my particular concern, do you all think I should get a GIA graded (graded August 06) 2.14ct E color with SB indpendently checked for color with a no UV light source?



The stone I am considering is in my other thread asking for opinions on the E VS1 with SB.



Thanks!



a

From what Marty was suggesting above with the GIA, that E has probably already factored in fluorescence, otherwise they would have bumped it to a D.

No, you are misinterpreting, that ''E'', might be a true ''F''

Yup that is my concern. Thanks Marty,

a

 

[stebbo]

Date: 9/20/2007 11:19:07 PM
Author: adamasgem

Date: 9/20/2007 10:17:47 PM
Author: stebbo



From what Marty was suggesting above with the GIA, that E has probably already factored in fluorescence, otherwise they would have bumped it to a D.

No, you are misinterpreting, that 'E', might be a true 'F'

No misinterpretation (just a different way of saying the same thing). If it was a true 'E', then they would have bumped it to a 'D', so it must be a fudged 'E' (hence as you say, a true 'F').

 

[WorkingHardforSmallRewards]

hum, I was thinking. If they are going to determine the color grade based on "perceived" color in certain natural lighting conditions, why not do the same thing with clarity?


I'm in the camp that says it is ridiculous to say that color should be graded on perception when certain lighting is causing for impurities in the diamond to react and cancel out the visibility of other impurities. The heart of the color grade, I understand, is the quantity of impure materials being present throughout the body of the diamond (though I am sure its more involved than that, I think you get the idea of what I mean yes?), thus making the diamond less rare and less valuable. The color is the end result of those impurities and to say that some of them are sometimes reacting thus sometimes "masking" the visible effects of those other impurities, thereby making it an excuse to omit the presence and very real effects of those impurities in the lab report seems to me no better than calling a VS1 Flawless just because in active non-grading lighting it might be perceived that way. Throw in a couple of halogen lamps and a nice bright sun with some light foliage on windy day and I bet you could turn just about any decent cut into a flawless diamond. anyway, not that I bear much respect in this community , but those are my thoughts


I just can't get my mind around the idea that they are offering up color grades to try to "make things easier on the consumer" when they have made clarity so difficult to translate into naked eye appearance? Does that make any sense? so I suppose, if they want to call a diamond "Eyeclean from 6 inches away" in some report they shouldn't do so by calling it "Flawless," and in the same way if they want to say "It looks whiter in UV light and more pure than it really is" they shouldn't do so by calling it a "D" which already has a definition (namely representing extreme purity and crisp whiteness REGARDLESS of lighting conditions, except of course when it is reflecting back something that is not a part of the diamond).

 

[adamasgem]

Date: 9/21/2007 1:33:44 AM
Author: WorkingHardforSmallRewards
hum, I was thinking. If they are going to determine the color grade based on ''perceived'' color in certain natural lighting conditions, why not do the same thing with clarity?

Well, I haven''t seen anyone advertize "Eye Clean at 12 Feet" yet from any lab, but it might be coming soon

European standards, a while back, specified clarity grades by the "absolute" size of the inclusion(s) using reticle, an attempt at getting away from the subjectivity issue.

The use of of some form of colorimetry is getting more prevalant, as others try to mimic and dumb down what I have try to do with the SAS2000. I firmly believe that the human has to be involved in the process also, even with the use of spectrophotometry. There are some things that can be done automatically, and then there are certain conditions where "blind" colorimetry cn give you a biased number due to the drawing of color fromm clarity and cleanliness influences.

Years back, I did study in Tucson where I had appraisers bring their master stones to be graded on an original Shipley bi stimulous colorimeter, and the I did the same experiment with my early SAS2000. What we found, embarassingly to the appraisers (and some labs), was that they had old bruted (unpoloshed) girdle masters that hadn''t seen acid since the day they were cut 30 years in the past. The draw of color was up to 3 or 4 color grades in certain instances because of the picking up of steel and other junk from tweezers and body oils, wax, etc on the girdle.

At least one major lab that I have visited in the past, which had bruted masters, at least boiied them in acid every night.

Faceted girdles are NOW mandetory for AGS masters, and I believe also GIA masters, and I''m proud to say that I had at least a "small" part in all of that.

What was mandated in the past, was that "masters" were supposed to be cape series stones (on the same hue line), however, no one in charge ever checked them in the past, and I''ve seen some real oddballs in different sets, and have rejected stones based on various criteria that unnecessarily drew color.

I don''t post a lot here because the trade is generally too cheap, and wants everything for free, and also some 600# gorrilas in the "trade" liberaly take credit for what they didn''t invent.

I dod a show and tell to a bunch of PhD''s in Carlsbad in the late 90''s, and what I was told was that in a later meeting that they (the PhD''s) said, well "we can do that". My understanding was that the head of GIA Gem Instruments, at the time, who was soon retired (and was one of the good guys there) told the group that they don''t do that. And the next thing I see is a GIA patent which first 1) misdefined what I was doing, and 2) specifically called out my SAS2000 system as one that didn''t work.

The head of GIA research at the time, after seeing my Liquid Nitrogen Immersion System (LNIS) demonstrated in Tucson, said to me that I should patent it, and I replied that I didn''t have enough moent to do do it, and secondly, how could I protect its unauthorized use of the concept. There is a little commentary about DeBeers, who beat their chest as the savior of the industry a year or so later for developing the technique. Only problem is that their patent priority date was over a year later than my public demonstrations and I admonished them in the Rapaport Report.

I have a little history in this. And the Internet helps a bit in exposing the frauds and crooks with truth.

I had the President of one major (secondary) lab call up and said he was going to sue me for everything I had, and I laughed and said "what did I do wrong" (except tell the truth, and secondly say that "take your best shot, discovery and interrogatorties will be very public and revealing and that I know the questions to ask", and by the way, I''m a "sole proprietor" and I don''t need an attorney to respond to any lawsuit. That was the last time I heard from him, as one of the pratices of the big firms is to try tobankrupt the little corporations with frivilous legal action, where they have to respond using an attorney, because they are incorporated.