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Fluorescence diamond..

lkean

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Apr 1, 2016
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All, I have been doing a lot of research and finally pulled the plug on a 1.5 carat AGS 000 heart and arrow diamond. I have research the effect of fluorescence on diamond pretty extensively. It is graded by AGS with medium blue fluorescence with I color VS1 clarity. HCA score is 1.0. When I received it, I am really happy because it really sparkles like a disco light. (ha..)

Today I took it to a highly respected GIA appraiser and he discounted the diamond at a 15% rate due to the fluorescence. A lot of sites including PriceScope are stating a 0% to +2% premium due to medium blue fluorescence on a I-color diamond. In addition the GIA appraiser also stated that fluorescence would cause light trajectory that enters the diamond to disperse/change. Thus fluorescence essentially voids the purpose of getting the highest cut grade diamond since light will not be reflected in the optimum manner.

I checked all over the internet and I still cannot find article that mention this negative effect of fluorescence on light reflection. Could someone please shine some light regarding this topic? Plus is medium fluorescence really cause a diamond's price to discount by 15%? Based on his appraised value, I am definitely overpaying even by buying my engagement ring on the internet. Help will be very much appreciated, thanks.
 

kenny

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lkean|1459548725|4014325 said:
All, I have been doing a lot of research and finally pulled the plug on a 1.5 carat AGS 000 heart and arrow diamond. I have research the effect of fluorescence on diamond pretty extensively. It is graded by AGS with medium blue fluorescence with I color VS1 clarity. HCA score is 1.0. When I received it, I am really happy because it really sparkles like a disco light. (ha..)

Today I took it to a highly respected GIA appraiser and he discounted the diamond at a 15% rate due to the fluorescence. A lot of sites including PriceScope are stating a 0% to +2% premium due to medium blue fluorescence on a I-color diamond. In addition the GIA appraiser also stated that fluorescence would cause light trajectory that enters the diamond to disperse/change. Thus fluorescence essentially voids the purpose of getting the highest cut grade diamond since light will not be reflected in the optimum manner.

I checked all over the internet and I still cannot find article that mention this negative effect of fluorescence on light reflection. Could someone please shine some light regarding this topic? Plus is medium fluorescence really cause a diamond's price to discount by 15%? Based on his appraised value, I am definitely overpaying even by buying my engagement ring on the internet. Help will be very much appreciated, thanks.
I'm suspicious of this so-called 'appraiser".
Does he by chance sell diamonds or directing you to certain diamond vendor(s)?

There is no such thing as a GIA appraiser.
First red flag.

GIA does not appraise diamonds.
It does educate diamond professionals so maybe this person was trained by GIA.
But whatever a graduate does is not backed up by GIA any more than Yale backs me up robbing a bank just because I got educated at Yale.
May I could tell the judge I'm a "Yale bank robber". :lol:

Why do you refer to him as a 'highly respected appraiser'?

I've been reading PS over 10 years and this is the first I've heard that fluor changes the direction of light inside a diamond ... which would mean fluor changes the index of refraction of diamond material.

Maybe it does.
I've just don't recall reading that.

Also, I think AGS grades light performance by measuring real light going through the diamond ... not just using math on a scan.
In this case I can't see how it can be wrong.

Next, this 15% thing.
Is your 'appraiser' saying you paid 15% less than you would have paid without fluor?
Is he saying you should have paid 15% less than what you paid?
Is he saying he is 'valuing' it at 15% of what he'd value it at if it had no fluor?

I have a bad taste in my mouth about the appraisal industry.
I've just read many examples of this garbage. :knockout:
 

lkean

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Thanks Kenny for taking the time to respond. I should correct myself that he is an appraiser I found at American Society of Appraiser. Here is an excerpt of his credential:

XXX is a Graduate Gemologist (GG) from the Gemological Institute of America (GIA), a title conferred upon completion of required courses and examinations in the theory and practice of gemology. He is an Accredited Senior Appraiser (ASA) with the American Society of Appraisers, and one of only a handful of Master Gemologist Appraisers® in the United States.

He also appears on National Geographic channel, so this person's credibility seems very sound.

He does not sell anything, just appraise jewelry. The appraiser said he is discounting the wholesale price based on the diamond's grade by 15% simply due to the fluorescence. And when I ask more about the effect of fluorescence, he said it would cause light trajectory going into the diamond to disperse. What he stated was this, "Out of the 4Cs, which is most important?" I said it is the cut. He said, "Yes, and you want the best cut for optimum light reflectivity. Haze would cause light going in to start zig-zagging (he draws it on paper)."

He demonstrate by covering the table lamp with a piece of white paper, and without. He explains that covering the light with a piece of paper is equivalent to having fluorescence on diamond. At last he recommends not to go with diamond with medium and strong fluorescence (if budget permits).

So I would like to know what I am missing, because I really didn't expect the 15% discount with an I-color diamond. Secondly I am also disappointed that HCA score of 1.0 does not seem to have any effect on the value of a diamond. I really like it because it really sparkles and get lots of compliment about how well it sparkles.

So I am trying to truly understand if there is reference that supports what he stated regarding fluorescence on price and light reflection. Thanks so much.
 

ADN

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lkean|1459554608|4014373 said:
Thanks Kenny for taking the time to respond. I should correct myself that he is an appraiser I found at American Society of Appraiser. Here is an excerpt of his credential:

XXX is a Graduate Gemologist (GG) from the Gemological Institute of America (GIA), a title conferred upon completion of required courses and examinations in the theory and practice of gemology. He is an Accredited Senior Appraiser (ASA) with the American Society of Appraisers, and one of only a handful of Master Gemologist Appraisers® in the United States.

He also appears on National Geographic channel, so this person's credibility seems very sound.

He does not sell anything, just appraise jewelry. The appraiser said he is discounting the wholesale price based on the diamond's grade by 15% simply due to the fluorescence. And when I ask more about the effect of fluorescence, he said it would cause light trajectory going into the diamond to disperse. What he stated was this, "Out of the 4Cs, which is most important?" I said it is the cut. He said, "Yes, and you want the best cut for optimum light reflectivity. Haze would cause light going in to start zig-zagging (he draws it on paper)."

He demonstrate by covering the table lamp with a piece of white paper, and without. He explains that covering the light with a piece of paper is equivalent to having fluorescence on diamond. At last he recommends not to go with diamond with medium and strong fluorescence (if budget permits).

So I would like to know what I am missing, because I really didn't expect the 15% discount with an I-color diamond. Secondly I am also disappointed that HCA score of 1.0 does not seem to have any effect on the value of a diamond. I really like it because it really sparkles and get lots of compliment about how well it sparkles.

So I am trying to truly understand if there is reference that supports what he stated regarding fluorescence on price and light reflection. Thanks so much.
Just because someone is on TV, it doesn't make them an 'expert' or necessarily even mean they have any idea what they're talking about...look at Jenny McCarthy :lol:
- There is a normal discount within the industry for Medium/Strong/Very Strong fluoro (regardless of whether it actually has an impact or not on the stone) - - how much can vary depending on the individual diamond.
- In some diamonds, the fluoro can cause the stone to look oily or hazy when in normal lighting - - it is a very small percentage, however you should get clarification from the valuer if he was speaking about your diamond being hazy specifically, or just in general as this will affect the value.
- There are a lot of very beautiful diamonds with medium-strong fluoro with no negative effect whatsoever - - and because of normal discounting, they are often more affordable. The valuer shouldn't be recommending what you should/shouldn't be buying...that's not their job...but putting that aside, he should know that not all diamonds are affected by fluoro, and to tell you to steer clear of them all...I'd ask him to clarify/justify that comment.
- The HCA has zero impact on a diamonds value - in fact, outside of this forum, most people (trade & consumer) have not even heard of it, or don't use it because of it's limitations. By it's own admission, it is a very basic rejection tool...not to be used for selection.
If you really like it...is there anything else that really matters?...
Hope this helps
 

ChristineRose

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lkean|1459554608|4014373 said:
And when I ask more about the effect of fluorescence, he said it would cause light trajectory going into the diamond to disperse. What he stated was this, "Out of the 4Cs, which is most important?" I said it is the cut. He said, "Yes, and you want the best cut for optimum light reflectivity. Haze would cause light going in to start zig-zagging (he draws it on paper)."

He demonstrate by covering the table lamp with a piece of white paper, and without. He explains that covering the light with a piece of paper is equivalent to having fluorescence on diamond. At last he recommends not to go with diamond with medium and strong fluorescence (if budget permits).
This makes no sense. Aside from the question of whether the discount actually reflects the market, this is not what would happen to the light. Haze in the sense of actual smoke would mess up the path of light, but fluorescence is not smoke.

A better analogy would be to imagine a disco ball in a disco. They turn off all of the lights but one spotlight and the whole room is covered by shiny little dots. But a disco ball in a normally lit room just looks like a sloppy mirror, and a disco ball outside in sunlight is shiny but the sparkle patterns are not visible at all.
 

Shelley9

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Hi just reading this post and interested as I am looking at buying a fluorescent Dimond as well as I had read with the lower grade colours they can show up whiter. I was also looking at an i colour. With the haziness that can affect some fluro diamonds how do you check for this? Does it show when looking at the diamond? Or does it have to be under certain lighting conditions? A very interesting topic.
 

diamondseeker2006

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Medium FL is almost never an issue. I wouldn't think twice about buying one. Strong blue is rarely an issue in a VS+ stone. You have to be more careful with Very Strong Blue. I have had a SBF stone before, and it most certainly was not hazy and the light return was great! I had a medium blue for over 25 years before I even found out it had fluorescence!!! I honestly do not know why some people have an irrational fear of FL. But I am thrilled that they sell at a discount! I see I color selling at a discount greater than 2% in my searches. If you want to tell us your stone's specs and the price, we can check prices for you.

Shelley, there is not that much UV light in most lighting conditions to count on it helping the color. I would not buy based on that. If you like I color, then the FL is just a nice natural feature to have.
 

gr8leo87

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1. All diamonds with fluorescence have an effect on price. Fluorescence in higher colour diamonds attract a much larger discount.

2. Statistically speaking nobody knows about HCA if I were to Round the percentages like GIA ;-).

Also it has been oft-repeated on this forum that HCA of 1.9 is not necessarily better than 0.9. So your diamond with HCA 1.0 isn't necessarily better or worse. So no effect on price there.

3. Fluorescence can cause haziness in Diamonds. But that happens in a small percentage of diamonds. You would notice these diamonds will not have a crispy look. Interesting theory on the haze disturbing the light paths and all that. But then again is your diamond hazy?

4. Also I don't think an I colour diamond with medium fluorescence would attract a 15% discount.
 

lkean

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All, thanks for the reply. I don't know what to believe because everywhere states that fluorescence in diamond with I-color and VS clarity actually has a 0% to +2% effect on price. So it is a bummer that a well respected appraiser immediately discount 15% from a diamond with medium fluorescence. Plus some sites even suggest to go for medium fluorescence in H to J color, but a well respected appraiser giving his honest opinion says he would not go for medium fluorescence and above because it affects light performance.

HCA below 1.0 was once discussed here to be potentially poorer light performance, but has better fire (eg. Tolkowsky spec has a 0.8 HCA score). I researched many examples of diamonds on Whiteflash website with higher and lower HCA spec. It comes down to preference, I concluded that I tend to like those between 0.9 and 1.2.

I think I can safely conclude that heart and arrow is just a marketing gimmick that I paid for. Fluorescence is actually not a good thing because it impacts light performance. Don't waste money going with AGS, GIA will do. Don't pay too much attention to HCA, just go with HCA < 1.9. Don't pay any premium for Idealscope, H&A scope image.
 

canuk-gal

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HI:

I am very confused.

Why would the appraiser discount the value of the diamond? If the corollary is that diamonds with Flouro are discounted, then shouldn't this already have been done at point of sale? Shouldn't your receipt be reflective of that--why the need to discount further? It begs the question: was the diamond was not priced as it could have been could have been?

For the OP--you don't sound happy about what has unfolded. And buying diamond, while stressful, should be a happy occasion or at least have a satisfying outcome. Is there any way we could be of (further) assistance?

cheers--Sharon
 

lkean

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All,
Hi! Yes it is a happy occasion, thanks for the reminder. The 15% discount is on his appraised price of my diamond. He looked at the wholesale price that day and applied 15% discount due to the medium fluorescence regardless whether it is I-color which contradicts what is posted even here at Pricescope. Based on a lot of the discussion about fluorescence here and other sites, I did not feel like blue fluorescence still carries that bad stigma that it is considered inferior nowadays.

I trust that he is impartial, but at the same time I would like to know if his statement about the effect of fluorescence is true. I really want to know if experts here have studied that fluorescence would cause light entering the diamond to zigzag. I read over-grading due to fluorescence article and the discussion, the 1997 GIA study etc and I somehow have never heard of this particular effect of fluorescence on light performance. Other posters have asked if the appraiser only sees this in my diamond, actually he explained fluorescence in general and recommended me to avoid fluorescence that is medium and up due to the inferior light performance.

I can still return this purchase if this is in fact inferior. Like he said, there is no point to pay for the most ideal cut for optimum light reflection yet get a diamond with medium and up fluorescence that would cause light entering to zig-zag. That is the main reason I would like to get to the bottom of this if possible. Thanks again, I apologize sounding negative in previous post.
 

lkean

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Thanks diamondseeker2006. Here is the diamond's spec:

Table: 57.5%
Depth: 60.9%
Crown <: 35
Pavilion <: 40.60
Girdle: Thin to slightly thick
Culet: Pointed (None)
Carat: 1.521
Color: I
Clarity: VS1
Cert: AGS 000 (ideal heart and arrow)
Fluorescence: Medium blue

Actually I think the main thing is to know if there exists the zig-zagging effect of light entering caused by fluorescence. Thanks.
 

kenny

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Question for KarlK, DiaGem, John Pollard and other experts ...

Does fluorescence change diamond's Index of Refraction?
 

Rockdiamond

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HI all,
lkean- I am in agreement with those that have said that there's no inherent worry in buying a Medium Blue FL stone.
The appraiser is misleading you by giving you the impression that Medium Blue fluorescence will impact the light performance in every case.
As has been mentioned, if a small percentage of MB or SB stones, the fluorescence causes a hazy appearance.
If that's the case you would immediately spot it yourself.
IN every other case, the answer is there's NO negative impact on light performance.
I agree with your research about price as well.
IN D-E-F-G colors MB or SB will cause a large discount.
IN I color it's generally not causing a discount in and of itself

Unfortunately this particular aspect is widely misunderstood and in fact there's a study under discussion now. This document is making false ( negative) claims about fluorescence right here on PS.
Here
 

ChristineRose

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kenny|1459626171|4014685 said:
Question for KarlK, DiaGem, John Pollard and other experts ...

Does fluorescence change diamond's Index of Refraction?
Refraction is caused when light is slowed by passing through a substance. When seen from any angle except head on (looking right into the light through the substance) the light appears to bend. The degree of refraction is dependent on the molecular structure of the substance. Different colors of light may have slightly different degrees of refraction.

Fluorescence is a light emitted by a substance in response to absorption of light of a different color.

The claim makes no sense whatsoever. If the molecular structure of a diamond changed, you'd know it immediately, and it wouldn't go back after you turned the UV off. Consider a brown diamond irradiated to make it green. If the structure did somehow change and go back, then there'd be no issue; the index of refraction would go back to where it was.

A diamond cut for ideal white light performance would not necessarily be cut for ideal blue light performance--that's the only thing I can come up with. That and the fact that the glow of fluorescence (at least in a disco) completely blocks the whole pretty much everything.

I was going to try and explain what the heck causes fluorescence in the first place and why most diamonds don't have it, but as I decided it can't be done without using the words "quantum mechanics" I decided not to go there.
 

gr8leo87

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lkean said:
All, thanks for the reply. I don't know what to believe because everywhere states that fluorescence in diamond with I-color and VS clarity actually has a 0% to +2% effect on price. So it is a bummer that a well respected appraiser immediately discount 15% from a diamond with medium fluorescence. Plus some sites even suggest to go for medium fluorescence in H to J color, but a well respected appraiser giving his honest opinion says he would not go for medium fluorescence and above because it affects light performance.

HCA below 1.0 was once discussed here to be potentially poorer light performance, but has better fire (eg. Tolkowsky spec has a 0.8 HCA score). I researched many examples of diamonds on Whiteflash website with higher and lower HCA spec. It comes down to preference, I concluded that I tend to like those between 0.9 and 1.2.

I think I can safely conclude that heart and arrow is just a marketing gimmick that I paid for. Fluorescence is actually not a good thing because it impacts light performance. Don't waste money going with AGS, GIA will do. Don't pay too much attention to HCA, just go with HCA < 1.9. Don't pay any premium for Idealscope, H&A scope image.
The effect on price is more complicated than you think.

I haven't come across premium for a fluorescent stone over a non fluorescent stone. Unless the fluorescent colours are green or red etc.

However if I were to assume a discount % for fluorescing stones - higher coloured diamonds would attract a larger discount compared to lower coloured diamonds - and that too if the body tint is within normal yellow range and not brown. So lets say a F medium attracts an additional 10% discount, the I medium would attract an additional 7%. Get my point?

I'm not really sure how much 'premium' you have paid for a well cut stone - but hearts and arrows is not a gimmick - and again depending on the premium that you have paid. I can assure you these stones come at a premium from the cutter - and these are much more beautiful to their non ideal counterparts.

I think it's just a case of you ending up with an appraiser who lacks understanding of all this. For him oranges are bananas and bananas are monkeys. I would suggest you find another appraiser.
 

gr8leo87

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Also there are some things that can cause light leakage in diamond - for example an oily Pavillion will cause a diamond's angle of incidence to be increase and be than the angle of reflaction - and when light falls within the angle of incidence it leaks.

Unless that haziness is increasing the angle of incidence of a diamond????
 

ChristineRose

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gr8leo87|1459657578|4014810 said:
Also there are some things that can cause light leakage in diamond - for example an oily Pavillion will cause a diamond's angle of incidence to be increase and be than the angle of reflaction - and when light falls within the angle of incidence it leaks.

Unless that haziness is increasing the angle of incidence of a diamond????
Passing through actual haze (smoke) would change the refractive of the diamond + smoke taken as a system. It would have no effect on the refraction in the actual diamond part.

The light from the fluorescence is not physical haze. It's just light that isn't part of the carefully designed cut of the diamond. That's why the light performance of the diamond can be impaired. But refractive index has nothing to do with it.
 

lkean

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Thanks Christine, so the appraiser is correct, fluorescence does impact light performance of a diamond. I am very surprise why this is not part of most diamond buying guidelines. I agree with the appraiser, we should not pay for the most ideal cut and go for diamond with fluorescence. I hope Pricescope would add this to their buying guideline. That allows other consumer to make the right decision, I sincerely hope Pricescope would publicize this information all over the place. I would have chosen differently should I have known about it earlier, thank you again Christine.
 

ringo865

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I don't believe it. I have a stone with strong blue fluorescence and its bright and not hazy at all. Medium blue should not cause a detrimental effect. Your stone is AGS 0 which is ideal light return. So.

I agree that you get a second opinion or, if you just plain don't like the stone, get a different stone. Before your return window closes.
 

lkean

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Hi Ringo, I guess it is not whether I like it or not. I am just an average Joe that need to buy an e-ring and trying to be an educated buyer. Many of us come to Pricescope to research and learn as much as we can from the big panel of experts and the wealth of information about diamonds available here.

I have spent 3-4 months reading lots of posts over here and elsewhere, and every time I thought I have learned enough to start the buying process and kept getting surprised how much more I have missed. Fluorescence was one area that I initially pretty much concluded to go with faint to none, then later learned that medium blue fluorescence could arguably be an added bonus to H-J color range diamond. I have then spent another 2-3 more weeks just to research fluorescence, the different color and its impact, read the potential over-grading article and discussion, and whether is has any negative impact. Like you, I did not realize fluorescence could impact light performance.

Again keep in mind that I am passing this information that I have learned from an independent Master Gemologist Appraiser which is not that many in this country, so this information is coming from a gemologist. Obviously I cannot defend nor argue his point of view. I have never heard about the impact he explained, thus I come here to seek help. From gemological point of view, if it is a fact that blue fluorescence causes non-optimal light reflection, then it is important to acknowledge that. So if it is indeed factual, then I agree with another point he made, there is no point in paying for an ideal cut diamond (for ideal light performance) and yet go for medium and higher fluorescence (which impact light performance).

Just like SI vs VS vs VSS etc, those inclusion may not be viewable unless you magnify it, but it is there. So I don't know if the existence of fluorescence and its impact is exactly that, it may not be visible by the naked eye but the impact is there.

Ha.. if anything I have learned about diamond, the belief/fact/trend just keep changing, eg Tolkowsky cut, then 60/60 or blue-white to white. So facts today may not be facts tomorrow. =)
 

darkfury18

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How did the appraiser explain this zigzag? Can you replicate the drawing he made?

The statement he made does not make sense. The following quote makes a reasonable explaination of what causes the hazy look in a fluorescent diamond, but it's not the fluorescence that causes it but other inclusions which impacts how lights moves through a diamond.

John Pollard|1459391156|4013509 said:
MissGotRocks|1459389725|4013497 said:
I would certainly trust your level of expertise far more that we consumers but the OP says the stone goes dark and cloudy in certain lighting conditions - sunlight and dim bar lighting. That's what led me to believe that she was seeing properties of ideal cut stones in those lighting situations rather than it being the stone itself.

At any rate, if she feels unhappy with the stone - and apparently she has felt this way for quite some time - it may be time to look at others.
Thank you for the kind comment. I think we're on the same page MGR... First, I am with you as it relates to "darkness." I'd reiterate that my gemological hypothesis about jhoshopgirl's diamond is speculation, based on cases I am familiar with. There's no way to confirm or dispel that speculation without pro analysis.

Second, I should say that "hazy" cases are quite disparate. Some - which many of us have seen these in fire-sale-discount-stores - look like dead, frozen spit. Others are only noticeable in certain conditions.

One related study is the concept of fluorescence causing cloudiness in diamonds. As you and other long-timers know, a diamond can have high levels of fluorescence with absolutely no adverse effects. With that said, there are also diamonds with a high frequency of microscopic pinpoints along with strong or very-strong fluorescence. In such cases the excitement of that fluorescence under UV can illuminate the pinpoints, creating a "hazy" look. Fluorescence has historically received blanket-blame for such "haze," but it can actually be two elements working together: One which is identified on the grading report ("accursed Fluorescence!") and a microscopic troublemaker that goes unmentioned (sneaky haze).
 

michaelgem

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lkean|1459705724|4014928 said:
Hi Ringo, I guess it is not whether I like it or not. I am just an average Joe that need to buy an e-ring and trying to be an educated buyer. Many of us come to Pricescope to research and learn as much as we can from the big panel of experts and the wealth of information about diamonds available here.

I have spent 3-4 months reading lots of posts over here and elsewhere, and every time I thought I have learned enough to start the buying process and kept getting surprised how much more I have missed. Fluorescence was one area that I initially pretty much concluded to go with faint to none, then later learned that medium blue fluorescence could arguably be an added bonus to H-J color range diamond. I have then spent another 2-3 more weeks just to research fluorescence, the different color and its impact, read the potential over-grading article and discussion, and whether is has any negative impact. Like you, I did not realize fluorescence could impact light performance.

Again keep in mind that I am passing this information that I have learned from an independent Master Gemologist Appraiser which is not that many in this country, so this information is coming from a gemologist. Obviously I cannot defend nor argue his point of view. I have never heard about the impact he explained, thus I come here to seek help. From gemological point of view, if it is a fact that blue fluorescence causes non-optimal light reflection, then it is important to acknowledge that. So if it is indeed factual, then I agree with another point he made, there is no point in paying for an ideal cut diamond (for ideal light performance) and yet go for medium and higher fluorescence (which impact light performance).

Just like SI vs VS vs VSS etc, those inclusion may not be viewable unless you magnify it, but it is there. So I don't know if the existence of fluorescence and its impact is exactly that, it may not be visible by the naked eye but the impact is there.

Ha.. if anything I have learned about diamond, the belief/fact/trend just keep changing, eg Tolkowsky cut, then 60/60 or blue-white to white. So facts today may not be facts tomorrow. =)
Speaking from the perspective of 30+ years of practice in the fields of gemology (FGA), appraising (NAJA) and diamond and gem cut design and light performance:

1.The notion that fluorescence in any way alters the light performance (changes the path light rays take through the gem) is false and misleading. As a previous poster states that would require a change in the diamond properties of refraction and dispersion, which are unaffected by the presence or lack of fluorescence.

2. Unlike the discounts for ST Blue and VST Blue, discounts for Medium Blue are unwarrented for any other reason than the general mistrust of blue fluorescence which began during the diamond investment craze of the late 70’s, early 80’s.

A read of the article: https://www.pricescope.com/journal/blue-fluorescent-diamonds-color-grading-issues

will make clear that blue fluorescence is a positive beauty attribute to be desired unless the amount of blue fluorescence causes the diamond to be graded higher by the GIA in their DiamondDock fluorescent lighting than the diamond appears in usual lighting where fluorescence is not stimulated.

Since this is unlikely and seldom the case for Med Blue you should be very happy with your purchase. In natural daylight with lots of fluorescence-stimulating UV your diamond will appear significantly whiter due to the masking effect of the blue on the complementary slightly yellow I color .
 

lkean

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Thank you very much Michael. It is reassuring to hear from an expert like yourself and RockDiamond to be on the same page. Btw I would like to say thanks, I can only speaks for myself that your article have provided lots of very useful information. Yes I have researched that article thoroughly, that is part of the reason I went with AGS just in case. One thing I did not mention, the appraiser thought my AGS graded I-colored diamond is either I, H or H+. Ha.. so there you have it.

That is all I need, assurances that what I understand holds. Gemologists agree on 90% of the things and from what I gather the difference in opinion is due to personal preferences and experiences. After all, it is an industry where beauty is in the eye of the beholder. So I will shrug off this one appraiser's personal opinion. Thanks all for the help, I truly-truly appreciate it, you have no idea!!
 

michaelgem

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372
lkean|1459714942|4015009 said:
Thank you very much Michael. It is reassuring to hear from an expert like yourself and RockDiamond to be on the same page. Btw I would like to say thanks, I can only speaks for myself that your article have provided lots of very useful information. Yes I have researched that article thoroughly, that is part of the reason I went with AGS just in case. One thing I did not mention, the appraiser thought my AGS graded I-colored diamond is either I, H or H+. Ha.. so there you have it.

That is all I need, assurances that what I understand holds. Gemologists agree on 90% of the things and from what I gather the difference in opinion is due to personal preferences and experiences. After all, it is an industry where beauty is in the eye of the beholder. So I will shrug off this one appraiser's personal opinion. Thanks all for the help, I truly-truly appreciate it, you have no idea!!
You are very welcome. The appraiser not being sure whether your I graded stone is an I, H or H+ is a real world example of the inconsistency inevitable when grading close to any fluorescent light whether that of the GIA DiamondDock or even a standard fluorescent desk lamp. If a medium blue diamond color graded I at 7inches in the AGSL DiamondDock, it would likely grade H or higher within 2-3 inches where the UV and VV are around 5 times greater.

That is why prior to 2000 GIA taught grading in daylight balanced artificial lighting absent grade whitening amounts of UV.
 

lkean

Rough_Rock
Joined
Apr 1, 2016
Messages
10
Yes, my case is one great example, color grading should not be that subjective with the presence of blue fluorescence. Thanks to you, I know I have made the correct educated buying decision. Have a good one.
 

ChristineRose

Brilliant_Rock
Premium
Joined
Aug 5, 2012
Messages
926
lkean|1459701782|4014909 said:
Thanks Christine, so the appraiser is correct, fluorescence does impact light performance of a diamond. I am very surprise why this is not part of most diamond buying guidelines. I agree with the appraiser, we should not pay for the most ideal cut and go for diamond with fluorescence. I hope Pricescope would add this to their buying guideline. That allows other consumer to make the right decision, I sincerely hope Pricescope would publicize this information all over the place. I would have chosen differently should I have known about it earlier, thank you again Christine.
This only applies to diamonds with very strong fluorescence. As stated, a diamond with very strong fluorescence can be appear hazy or oily in strong sunlight. It will not be an issue with your diamond. Truly strong fluorescence is very rare, and people actually pay a premium for it because it's, well, cool. This is discussed on the guidelines but it's a non-issue for most people as the true overblues are generally sold as such nowadays.

The fear of fluorescence has caused the value of it to go up and down over the years, but the experts on here do not think 15% for a medium blue is warranted. You will see nothing from a medium blue unless you use an actual UV light.

The issue of whether an G is really an G or is an I which looks whiter in some lights, is a different one. Either way, it looks how it looks.
 

ADN

Shiny_Rock
Trade
Joined
Nov 24, 2015
Messages
311
ChristineRose|1459725712|4015065 said:
lkean|1459701782|4014909 said:
Thanks Christine, so the appraiser is correct, fluorescence does impact light performance of a diamond. I am very surprise why this is not part of most diamond buying guidelines. I agree with the appraiser, we should not pay for the most ideal cut and go for diamond with fluorescence. I hope Pricescope would add this to their buying guideline. That allows other consumer to make the right decision, I sincerely hope Pricescope would publicize this information all over the place. I would have chosen differently should I have known about it earlier, thank you again Christine.
This only applies to diamonds with very strong fluorescence. As stated, a diamond with very strong fluorescence can be appear hazy or oily in strong sunlight. It will not be an issue with your diamond. Truly strong fluorescence is very rare, and people actually pay a premium for it because it's, well, cool. This is discussed on the guidelines but it's a non-issue for most people as the true overblues are generally sold as such nowadays.

The fear of fluorescence has caused the value of it to go up and down over the years, but the experts on here do not think 15% for a medium blue is warranted. You will see nothing from a medium blue unless you use an actual UV light.

The issue of whether an G is really an G or is an I which looks whiter in some lights, is a different one. Either way, it looks how it looks.
Hi :wavey: - just a comment on the above that's in bold - - I've bought & sold many stones with fluoro, but i've certainly never charged a 'premium' - - regardless of whether or not they should be discounted within the trade (this is a seperate thread that others can discuss ;-) ), the fact is that strong/v strong are usually sold at a significant discount, and those savings are then passed onto the consumer, which is why you can find a really beautiful stone with strong/v strong that may normally be out of budget without fluoro. The only people that have paid a 'premium' on strong/v strong fluoro would be unsuspecting consumers purchasing from a retailer that has perhaps used some clever marketing techniques to justify a 'premium'...I can guarantee that the retailer certainly wouldn't be paying a premium from the cutter/wholesaler for strong/v strong fluoro...
 
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