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Another Fluorescence ques....in bars/clubs
- Thread starter uvaray
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I disagree. Experts other than those you agree with claim that these characteristics can cause a problematic appearance in natural daylight. I am not willing to characterize anyone who sees it this way as biased and spinning a false narrative anymore than I am willing to characterize those who see it your way as biased and spinning a false narrative. People are allowed to have different viewpoints, in the field, and still be honorable and still be experts. THAT''S WHY IT''S CONTROVERSIAL.
Date: 6/22/2010 1:49:03 PM
Author: John Pollard
Date: 6/21/2010 6:34:31 PM
Author: Isabelle
John, as always your knowledge is overwhelming. So interesting to note that they''re hard to even find these days and that the discount isn''t usually that much. But then why did that other PSer say she was able to get a much larger stone by going with strong fluor? In any case, when I''m back on my computer I''ll read the article you linked to. I''m currently posting from iPhone which is hard.
You''re welcome for the info. I wanted to mention that I also enjoyed reading Wink''s historical perspective.
AGS doesn''t downgrade for fluorescence. No lab does, that I know of.
It may be helpful to offer this perspective: Fluorescence discounting becomes somewhat negligible when you compare it to discounting in categories considered more significant, like color or clarity. Move from D to E in color, or IF to VVS in clarity and you''ll find a meaningful discount. Now try moving 5 grades. And, like fluorescence, the discounts may or may not reflect something that''s visible to the casual viewer.
On the overall topic GIA''s study concludes well, and offers a gentle spanking to trade members who would carrry on old wives'' tales about the ''evils'' of fluorescence:
''Unlike the notion held by many in the trade, fluorescent diamonds are not as prevalent as nonfluorescent stones, as the GIA Gem Trade Laboratory sample data for more than 26,000 diamonds showed. The present study also challenges the trade perception that fluorescence usually has a negative effect on better-color diamonds. Our results show that the diamond industry would be better served by considering each individual diamond on its own visual merits.''
Having given this perspective, it''s also important to say that it is anyone''s right to HATE fluorescence. No problem. I defend their right to hate it. To spit when they hear it. To curl their fists aloft and with angry howls break the clouds!
In such matters involving personal preference we should just remember that - as we exercise our own right to choose - it''s a good idea to respect that others may choose differently... whether fluoro, color, clarity, cut or pie flavor. It''s a two-way street.
Well said. And I do respect the rights of many experts to hold one view while other experts see things differently. And I assume there is controversy for a reason. I stand corrected on the AGS grading comment.
Dreamer_D
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Date: 6/22/2010 2:38:03 PM
Author: Rockdiamond
Date: 6/22/2010 1:49:03 PM
Author: John Pollard
Date: 6/21/2010 6:34:31 PM
Author: Isabelle
John, as always your knowledge is overwhelming. So interesting to note that they''re hard to even find these days and that the discount isn''t usually that much. But then why did that other PSer say she was able to get a much larger stone by going with strong fluor? In any case, when I''m back on my computer I''ll read the article you linked to. I''m currently posting from iPhone which is hard.
You''re welcome for the info. I wanted to mention that I also enjoyed reading Wink''s historical perspective.
AGS doesn''t downgrade for fluorescence. No lab does, that I know of.
It may be helpful to offer this perspective: Fluorescence discounting becomes somewhat negligible when you compare it to discounting in categories considered more significant, like color or clarity. Move from D to E in color, or IF to VVS in clarity and you''ll find a meaningful discount. Now try moving 5 grades. And, like fluorescence, the discounts may or may not reflect something that''s visible to the casual viewer.
On the overall topic GIA''s study concludes well, and offers a gentle spanking to trade members who would carrry on old wives'' tales about the ''evils'' of fluorescence:
''Unlike the notion held by many in the trade, fluorescent diamonds are not as prevalent as nonfluorescent stones, as the GIA Gem Trade Laboratory sample data for more than 26,000 diamonds showed. The present study also challenges the trade perception that fluorescence usually has a negative effect on better-color diamonds. Our results show that the diamond industry would be better served by considering each individual diamond on its own visual merits.''
Having given this perspective, it''s also important to say that it is anyone''s right to HATE fluorescence. No problem. I defend their right to hate it. To spit when they hear it. To curl their fists aloft and with angry howls break the clouds!
In such matters involving personal preference we should just remember that - as we exercise our own right to choose - it''s a good idea to respect that others may choose differently... whether fluoro, color, clarity, cut or pie flavor. It''s a two-way street.
I agree with a lot of what you wrote John- I''m a big advocate for the ''live and don''t insult other''s taste about diamonds '' part.
We might have a different perspective on the pricing issue- because we''re buying polished from a many sources- meaning that strong blue stones, which are already on the market are what I based my statement on.
Since you are representing a cutter, the discounts you offer for a strong blue might be much smaller ( justifiably so) as compared to stones on the general market.
I do disagree, slightly, about the part in bold- in one specific area. That being Fancy Light, Fancy Yellow, and Fancy Intense Yellow stones with strong blue.
It would be possible to make a case that GIA is tougher on these colors when they are strong blue- although part of this has to do with the stronger effect on perceived color these stones experience. The result is that a Fancy Yellow with Strong blue, viewed in ''normal'' lighting, may have a color as strong as an inert Fancy Intense Yellow.
I love this thread. I love how much I can learn just reading what you guys say to each other. Thanks David.
Allison D.
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Stone, the history of ACAs not allowing fluorescence has more to do with 'purist' roots (which I know John has alluded to previously) than with performance. Most would agree that fluorescence in the faint to medium range doesn't impact performance, and yet it wasn't allowed in the ACA brand at all.
As Wink's commented, it's been a tough haul and long curve in trying to move people away from negative connotations they've associated with fluorescence. It's easy to see why it might make more sense to avoid the issue of fluorescence altogether by disallowing it from the brand. There's already significant energy spent in trying to educate about the impact of cut quality just without also having to overcome a preconceived aversion to fluorescence.
Date: 6/22/2010 3:53:03 PM
Author: Allison D.
Date: 6/22/2010 1:00:26 PM
Author: dreamer_d
Date: 6/22/2010 8:01:53 AM
Author: Isabelle
That''s sort of sophistry though, isn''t it Dreamer? McDonalds isn''t known as the world''s finest purveyor of burgers. A better analogy would be for you to say that you don''t consider Ferrari to be a source of pure unbiased information about how to make a fast sports car. They might not be unbiased about their own cars, but I think most people would defer to their expertise on on how to make one run fast.
I think McDonald''s has perfected the art of marketing its goods to its target population and highlighting or spinning information in a way that meets its needs, and therin lies my comparison with a multinational corporation like Tiffany. You may not see the parallel, but I certainly do. And I would also take with a grain of salt the information that Ferrari provided in marketing information for its consumers, especially when some of that information was contradicted by many other experts.
Hee hee - lest anyone think I was talking about the ''mcdonald''s equivalent'' of a PS expert earlier....in my case, it wasn''t Tiffany.
The topic of the GIA study came up in conversation with a well-respected PS vendor, and he was fairly emphatic in his disagreement with the results. He felt that it (VSB) has to affect light performance in stones at least 2/3 of the time.
Since that''s not my area of training, I didn''t debate and we moved on.
Like any other highly technical field, experts can and do disagree from time to time, and in those cases the answer is somewhere short of absolute.
So true Allison! That''s precisely why it''s controversial; why these stones cost less to buyers like David (Rock Diamond); why Tiffs and others recommend against them; and why Pricescope itself says "Don''t buy unless you can see it in natural daylight and confirm that there isn''t a milky issue." (paraphrase)
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Fluor is the result of material absorbing a certain wavelength of electromagnetic radiation that excites the electrons, and when they jump back to lower energy states they release the energy by emitting a certain visible wavelength, since the boron is throughout the stone the stone looks "blue" uniformly, and in slight amounts can help the body colour, but remember the fluoro is not actually affecting the stone's body colour, it just looks that way, so a light ray that enters, is reflected, and exits undispersed will still be whatever colour the body colour of the diamond is, though against a slightly "bluer"("whiter", if J/K, say) background I suspect that among those who can see the difference in 'hue', they will perceive it differently
Dreamer_D
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Date: 6/22/2010 4:27:20 PM
Author: Allison D.
Stone, the history of ACAs not allowing fluorescence has more to do with ''purist'' roots (which I know John has alluded to previously) than with performance. Most would agree that fluorescence in the faint to medium range doesn''t impact performance, and yet it wasn''t allowed in the ACA brand at all.
This is my gut feeling as well based on what I know about the brand and brands in general.
And more generally, of course a brand is free to make any rules it likes about what is allowed and what is not allowed, as does Tiffany wrt clarity and color in addition to flour. But none of these brand preferences offer proof positive that a given characteristic -- be it SI2 or J color or SB flour -- is "bad" overall and should be avoided, nor should such preferences be taken as proof of the benefit or costs of those characteristics.
As Wink''s commented, it''s been a tough haul and long curve in trying to move people away from negative connotations they''ve associated with fluorescence. It''s easy to see why it might make more sense to just avoid the issue altogether by disallowing it than the spend a huge amount of time trying to change people''s minds.
Especially since, ultimately, "the diamond industry" (whoever these people are) has nothing to gain from educating the public about flour -- why should the industry in general care if people are misinformed about flour, or color, or clarity or anything else? Misinformed consumers are easy to sell to, and that might be a positive to many diamond vendors. Present company excluded of course.
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I have never, ever, ever seen a VS2 graded by GIA or AGS that had an eye visible inclusion. I can''t imagine a round brilliant VS2 with an inclusion you could see. I guess it could be possible with a less faceted cut though. It might interest you to know that Tiffany & Co. (AKA ''the McDonalds of the diamond industry'' LOL)recommends a higher clarity grade than VS2 for Emerald cuts for example.
stone-cold11
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Allison D.
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stone-cold11
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At least one forum goer I helped can see VS2 inclusions in her round cut, IIRC it was a JA stone GIA graded, and she has to do a return and get a VS1. So eye-clean is also dependent on individual''s eye-sight, so that is an arbitrarily cut off.Date: 6/22/2010 4:50:15 PM
Author: Isabelle
I have never, ever, ever seen a VS2 graded by GIA or AGS that had an eye visible inclusion. I can''t imagine a round brilliant VS2 with an inclusion you could see. I guess it could be possible with a less faceted cut though. It might interest you to know that Tiffany & Co. (AKA ''the McDonalds of the diamond industry'' LOL)recommends a higher clarity grade than VS2 for Emerald cuts for example.
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stone-cold11
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Actually, clarity grading is not based on if the inclusion is visible. That''s why I1''s can be eye clean, and VS2''s not eye clean.
I have seen a VS2 round diamond who''s imperfection was visible naked eye.
The case I recall was a large stone ( about 3cts) and the tiny imperfection was simply in the wrong place at the wrong time!
However this is extremely rare in a round diamond, therefore advising someone who''d gotten one like that to move up to VS1 might be needlessly increasing the budget.
I have seen a VS2 round diamond who''s imperfection was visible naked eye.
The case I recall was a large stone ( about 3cts) and the tiny imperfection was simply in the wrong place at the wrong time!
However this is extremely rare in a round diamond, therefore advising someone who''d gotten one like that to move up to VS1 might be needlessly increasing the budget.
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Arbitrary? Right. Come to think of it, I am pretty sure that Steve Austin The 6 Million Dollar Man could see an inclusion in a VVS2, so that''s probably arbitrary too. But for most of the human world, VS2 is generally understood to mean the inclusion is not visible with a loupe, let alone the naked eye. --Particularly in a RB.
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I agree David. And wouldn''t it be more likely that the gem grader made a mistake in the grading on that particular diamond? I have read that VS2 means not visible with a loupe. VVS2 means not visible without a microscope to the power of (10? 20?)--Can''t remember. I have an SI1, and it''s visible with a good set of contact lenses on if you examine the pavilion.
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clarity grading w/ 10x loupe
GIA: http://www.gia.edu/lab-reports-services/about-the-4cs/index.html
AGS: http://agslab.com/ags_grading_system_diamond_clarity_grade.php
EGL: http://www.eglusa.com/clarity.html
IGI: http://www.igi-usa.com/igi-clarity.html
HRD: http://www.hrdantwerp.be/content/certification/certificates/about_diamond_certificates/the_4cs.htm
GIA: http://www.gia.edu/lab-reports-services/about-the-4cs/index.html
AGS: http://agslab.com/ags_grading_system_diamond_clarity_grade.php
EGL: http://www.eglusa.com/clarity.html
IGI: http://www.igi-usa.com/igi-clarity.html
HRD: http://www.hrdantwerp.be/content/certification/certificates/about_diamond_certificates/the_4cs.htm
stone-cold11
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Yes I made a mistake. I didn''t realize one could see 10X with a standard loupe. Thank you, again, for pointing out my error. But can we stop pretending that it''s "arbitrary" to use VS 2 as a cut off for a clarity rating, or is the narrative against Tiffany just too tempting to let it go? I think we both know that you can''t see inclusions in a VS2 diamond with the naked eye unless it is graded wrong, it''s an emerald cut, or the occurrence is so rare that it is merely an anomaly.
stone-cold11
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Date: 6/22/2010 5:31:22 PM
Author: Isabelle
Noted. Thank you.
I went to my jeweller a long time ago and he had a 6.3ct RB. Gorgeous stone, but the (GIA) VS2 inclusion was frankly clear as day, no loupe needed. He told me that when GIA teaches clarity they use 0.5ct stones as the basis for the clarity grades, and the system rather falls apart as you get larger and larger - hence why people say it's safe to bet that a 0.3ct may well be eyeclean but good luck finding that in a 3ct stone that isn't cloudy or wispy to the detriment of brilliance
I hope one of our board experts will chime in on exactly how the scale changes when grading larger stones, and how those changes are kept uniform throughout the various agencies & countries in which a lab operates
ETA: I think Tiffany is overpriced, but if someone is looking for the experience it's certainly one option and they're guaranteed to get at minimum a well-performing stone - my Tiffs baby bezels are my favourite earrings, and they're stunners. I don't think anyone is browbeating Tiffs, their goods, or their marketing - it's obviously very successful. That doesn't make them objective source of information.
Past, Present, Future: The Meaning of Three-Stone Engagement Rings
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