shape
carat
color
clarity

Fluorescence-AGS question

Stephan

Ideal_Rock
Joined
Feb 13, 2003
Messages
2,917
This is very interesting Paul.
It could be a suggestion for all super ideal cut diamonds sellers (you and the others) to give an honest opinion on the presence of fluorescence in each diamond because we can't relay on the grading reports. I know you are all sincere when saying that the appearance of a diamond you are selling is not impacted, but it will help consumers to make an informed decision because the market today is still pricing this particularity. An Asian friend of mine sets and sells diamonds here in Brussels, he checks every diamond for fluo even if not mentioned in the report. He rejects them because it is his believe that fluorescence is bad. So imagine if a super ideal cut diamonds seller disappear from the market, and you just bought a D color that is really fluorescent but not mentioned on paper. It will be very difficult to sell without a big loss.
What happens if one of the diamonds you are selling is D color GIA none or AGS negligible but when you check it is medium fluo?
Do you adjust the price accordingly, or do you consider yourself lucky?
I saw 2 examples recently (and not CBI diamonds) of people who were surprised to see this feature, that means they were not informed.
 

OoohShiny

Ideal_Rock
Premium
Joined
Apr 25, 2014
Messages
8,228
In follow-up of this thread, I asked my team to check fluo on all GIA-None passing by in our office, and to photograph whenever there was fluo, despite the grade being None. Literally, the first stone passing our office today already was bingo.

GIA-report-number is 2141960645, https://www.gia.edu/report-check?reportno=2141960645&s=1544456425618

And this is the pic, borderline Medium according to our internal assessment
GIA2141960645.jpg

Live long,
Great pic :)

May I ask if you are using 365nm lamps or a wider/different range?


Dear Eva,
1. The UV used to ID gems is a standard for a different purpose. It is wrong for the fluoro effect with diamonds.
2. Labs issue Reports not Certificates. Big difference.
3. 365 creates very little Fluorescence and since that is what we are studying simple and variable cheap visible UV tools are more relevant than 365nm because there is very little 365 in human environments vs there is heaps of the UV and visible violet that create the most N3 excitation.
From https://www.gia.edu/gems-gemology/summer-2013-luo-fluorescence-optical-defects
(I added the black line at about 365nm and the purple line to indicate that the energy that contributes the most is way way above 365nm and well into the visible spectrum).
Capture.JPG

@Garry H (Cut Nut)
aa fluorescence.jpg
Fluorescence (bottom left)
The maximum fluorescence emission is shown on the bottom left graphic (the blue line). It is clearly visible that the maximum pick is at 365nm.
The bottom right graphic (red line) shows the PLE (photoluminescence excitation).

Sorry to ask a dumb question... but is the blue, bottom left graphic not the 'emissions' graph (therefore showing the wavelengths given off by the diamond during fluorescence)?

And the red, bottom right graphic (as referenced by Garry) not the 'excitations' graph (therefore showing the wavelengths that create excitation within the diamond)?

If so, is it not the case that the graphs show that the wavelengths creating a fluorescent response within a stone are different to the wavelengths that are emitted during the fluorescent response?

So, in effect, Input Wavelength != Output Wavelength?

Because, presumably, the light energy involved in creating the fluorescence results in a change in the light energy output after the excitation process??


[/guessing]
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
In follow-up of this thread, I asked my team to check fluo on all GIA-None passing by in our office, and to photograph whenever there was fluo, despite the grade being None. Literally, the first stone passing our office today already was bingo.

GIA-report-number is 2141960645, https://www.gia.edu/report-check?reportno=2141960645&s=1544456425618

And this is the pic, borderline Medium according to our internal assessment
GIA2141960645.jpg

Live long,
Hi Paul,
We also see GIA "none" with some level of fluoro come through our operation from time to time. And there have been threads here on the forum from consumers on the issue. I know I have seen more recent threads, but here is one example.
https://www.pricescope.com/community/threads/gia-fluorescence-none-can-someone-explain.5865/
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
If so, is it not the case that the graphs show that the wavelengths creating a fluorescent response within a stone are different to the wavelengths that are emitted during the fluorescent response?

So, in effect, Input Wavelength != Output Wavelength?
Correct.
What you see with the eye can be one or more of several different colors(wavelenths).
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Great pic :)

May I ask if you are using 365nm lamps or a wider/different range?

Sorry to ask a dumb question... but is the blue, bottom left graphic not the 'emissions' graph (therefore showing the wavelengths given off by the diamond during fluorescence)?

And the red, bottom right graphic (as referenced by Garry) not the 'excitations' graph (therefore showing the wavelengths that create excitation within the diamond)?

If so, is it not the case that the graphs show that the wavelengths creating a fluorescent response within a stone are different to the wavelengths that are emitted during the fluorescent response?

So, in effect, Input Wavelength != Output Wavelength?

Because, presumably, the light energy involved in creating the fluorescence results in a change in the light energy output after the excitation process??

[/guessing]
@OoohShiny,
Not a dumb question!
Excitation and Emission are the two sides of the fluorescence coin.

Emission (the actual fluorescence -such as the blue light given off) will be lower energy (longer wavelength) than than the energy necessary to excite it (shorter wavelength).

It's important when trying to make sense of the graphs to distinguish between the two!

The 'black light' is shining light waves in invisible (UV) part of the spectrum. Some of those waves may stimulate a defect center causing a diamond to emit wavelengths in the visible part of the spectrum. Thus, we see the diamond 'glow in the dark'.
 
Last edited:

Johnbt

Shiny_Rock
Premium
Joined
Mar 13, 2018
Messages
313
"This is very rude, and overall an ignorant statement."

I wasn't offended, maybe she truly is smarter than everybody else. I can't imagine the frustration I'd experience if I had to go through life always being the smartest person in the room.

Heck, some of my best friends are engineers. Or lawyers. :lol:
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
18,423
@Garry H (Cut Nut)
aa fluorescence.jpg
Fluorescence (bottom left)
The maximum fluorescence emission is shown on the bottom left graphic (the blue line). It is clearly visible that the maximum pick is at 365nm.
The bottom right graphic (red line) shows the PLE (photoluminescence excitation).
Eva that is an "artifact"- you need to read and understand the article. That is not a real blip.
Twice in the article they make this point: "For example, the intensity of N3 luminescence (measured at 439 nm) when excited by 400 nm excitation is approximately double that of the same emission measured at 360 nm excitation (figure 6)."
Please understand that while I am a mere simpleton and jeweller I am also a geologist and not a total moron.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
18,423
Great pic :)

May I ask if you are using 365nm lamps or a wider/different range?






Sorry to ask a dumb question... but is the blue, bottom left graphic not the 'emissions' graph (therefore showing the wavelengths given off by the diamond during fluorescence)?

And the red, bottom right graphic (as referenced by Garry) not the 'excitations' graph (therefore showing the wavelengths that create excitation within the diamond)?

If so, is it not the case that the graphs show that the wavelengths creating a fluorescent response within a stone are different to the wavelengths that are emitted during the fluorescent response?

So, in effect, Input Wavelength != Output Wavelength?

Because, presumably, the light energy involved in creating the fluorescence results in a change in the light energy output after the excitation process??


[/guessing]
You are correct OhShiny, and I deliberately cut off the artifact that appears to the right of the graph I posted so as not to confuse people who have not read and understood what an artifact is.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
A lot of things with the diamond industry are frustrating for engineering types.
Being one it took me a while to get mostly over it and some days even after 15 years here it flairs up.
Lets keep it classy so the mods don't have to step in.
 

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
@Paul-Antwerp
Much more on the report are facts! All measurements, plot of inclusions for example.
But yes, color, clarity and fluorescence are subjective terms.
@Johnbt
It is difficult to discuss a subject when someone miss certain knowledge.
@OoohShiny
You should read what the fluorescence is before to write your comment.
@Texas Leaguer
Excellent answer to @OoohShiny question.
@Garry H (Cut Nut)
I read the article completely, but let point, that this article's subject is not the scientific research of the fluorescence in common, but the fluorescence in known optical defects in diamonds. From 25 examined diamonds, only 6 are not fancy colors in this GIA research.
@Karl_K
Making you knowledgeable is certain field does not automatically make you an expert in everything.
 

Johnbt

Shiny_Rock
Premium
Joined
Mar 13, 2018
Messages
313
"It is difficult to discuss a subject when someone miss certain knowledge."

That's what we keep telling you. Heck, you haven't even answered my question about what kind of UV light you're using or commented on how you managed to overlook the Kelvin temperature scale when you were preaching about how ignorant everyone was about scientific standards.

We're being nice and just having a little discussion here. This isn't a formal debate and there will not be a winner declared.
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
18,033
Seriously. This isn't a debate class, and no points are awarded. All this thread shows me is that @EvaEvans is not willing to listen to or respect expert opinion, and is extremely rude.
 

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
"It is difficult to discuss a subject when someone miss certain knowledge."

That's what we keep telling you. Heck, you haven't even answered my question about what kind of UV light you're using or commented on how you managed to overlook the Kelvin temperature scale when you were preaching about how ignorant everyone was about scientific standards.

We're being nice and just having a little discussion here. This isn't a formal debate and there will not be a winner declared.
First, your comment for Kelvin temperature had absolutely no connection with my point so why even to make the effort to answer you?
You should learn what is the SI system and scientific measurements. Learn what is measurements vs scientific measurements and why the standardization is absolute requirement in the science field.
Also learn to comment ONLY the specific subject in the thread as I do.
I still have the feeling that you missed my point WHY the standardization is needed to make any lab result ligament!
It is NOT enough to say: fluorescence is "none", if the wave length is unknown or within wide range. So here come the standard: the fluorescence in diamonds is measured at 365nm. @Garry H (Cut Nut) pointed, that the standard should be at 385nm. I answered that for me it doesn't matter the specific wavelength, but the standard.
My example with the scientific temperature standard was ONLY an example, giving you more clarity why diamond dimension on the lab report is in mm, not in inch, similar to why the science uses Celsius, not Fahrenheit, although in the USA the common temperature measurement is Fahrenheit.
Last, the Kelvin temperature is the same scale as of Celsius, so again, you just redirected the discussion.
 

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
A lot of things with the diamond industry are frustrating for engineering types.
Being one it took me a while to get mostly over it and some days even after 15 years here it flairs up.
Lets keep it classy so the mods don't have to step in.
@Karl_K
The inventor of Octavia Cut!
I feel some kind of sarcasm in your comment. But let me tell you, that your invention wouldn't be possible without the engineer work and you should respect and appreciate the engineering.
Your computer, the program that you use to develop your Octavia cut, the Sarin machine, the ..., the ... the whole world that we are living in is better thanks to the engineer work.
We are talking here about Fluorescence but the Fluorescence will be unknown without the science development. Without the engineering the UV lamp will not be constructed.
Engineering stays in the background of the developing of the diamond industry and diamond business nowadays.
Without the technical equipment the GIA/AGS will not be able to create their "reports".
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
@Karl_K
The inventor of Octavia Cut!
I feel some kind of sarcasm in your comment. But let me tell you, that your invention wouldn't be possible without the engineer work and you should respect and appreciate the engineering.
Your computer, the program that you use to develop your Octavia cut, the Sarin machine, the ..., the ... the whole world that we are living in is better thanks to the engineer work.
We are talking here about Fluorescence but the Fluorescence will be unknown without the science development. Without the engineering the UV lamp will not be constructed.
Engineering stays in the background of the developing of the diamond industry and diamond business nowadays.
Without the technical equipment the GIA/AGS will not be able to create their "reports".

Yep that's all I am is the designer of the Octavia cut, it is just not possible that my degree is in EET and that I have built a computer from chips and parts.
That is sarcasm fwiw. It is also true about the computer and my degree.
But this thread is not about me.

Grading reports are opinion not a scientific sound document. They even say so on the back.
That bugs me but it is what it is. That is what I was referring to.
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
18,033
Come on, mods. Are we seriously going to let @EvaEvans insult valued members of the forum for literally no reason???? This thread is so frustrating. @Karl_K you are so patient.
 

Paul-Antwerp

Ideal_Rock
Trade
Joined
Sep 2, 2002
Messages
2,859
@Paul-Antwerp
Much more on the report are facts! All measurements, plot of inclusions for example.
But yes, color, clarity and fluorescence are subjective terms.

Hi Eva,

Trying to keep this a positive exchange, but even here, you are only partially right.

Measurements, you say. I agree on 1 in 3.

- Millimeter depth, yes, that probably cannot be questioned.
- Millimeter diameter, most people would bet that is a fact too. But did you know that it is biggest diameter and smallest diameter for most shapes (round, oval, pear, ...), but that in square-shapes, it is not. And some labs mention other sets of diameters for patented shapes or faceting patterns, with the resulting percentages in depths and table-sizes being based on a totally arbitrarily chosen diameter?
- And I am forgetting the obvious. All the angles mentioned are averages, and in the case of GIA, they are even rounded for whatever reason.

Plots of inclusions are your second fact. Possibly, in the sense that they are an opinion of what a human grader sees in a diamond. And not only every lab, every grader plots differently. True, a plot probably indicates an inclusion definitely present, sufficient as assistance to identify a diamond, but is the plot complete? Or possibly even exaggerated?

But for the purpose of this thread, can we go back to the photo I posted. GIA stipulates a fluorescence designation of ‘none’ for that diamond, and others we encounter, while there is clearly some level of fluorescence. How can this be considered factual?

And to add to history, when AGSL moved to the grade of Negligible, it was related to the potential problem of naming something that is not 'zero' with the term 'Nil' or 'None'.

Live long,
 

Ella

Brilliant_Rock
Staff member
Premium
Joined
Jan 18, 2010
Messages
1,622
Folks, keep it polite or we will be giving time outs. @EvaEvans , please be respectful or we will give you a time out from the forum.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Plots of inclusions are your second fact. Possibly, in the sense that they are an opinion of what a human grader sees in a diamond. And not only every lab, every grader plots differently. True, a plot probably indicates an inclusion definitely present, sufficient as assistance to identify a diamond, but is the plot complete? Or possibly even exaggerated?
When I was searching for stones for clients while working for dbl, I would often have the plot open next to images of the diamond and many times I would be thinking how in the world did they get that plot from what was in the diamond?
I also think that maybe since the gia expansion that plots have been one area where they have really gone down hill.
Not having a huge historical experience, they may have always been that bad.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
18,423
@Garry H (Cut Nut)
I read the article completely, but let point, that this article's subject is not the scientific research of the fluorescence in common, but the fluorescence in known optical defects in diamonds. From 25 examined diamonds, only 6 are not fancy colors in this GIA research.

Eva I have my own evidence and experiments plus that of an unpublished article confirming that the N3 blue fluoro is alive and well from the near visible and visible UV range. There has been a very long discussion on PS where I have argued this point over several years.
You have missed that point and seem not to be interested in anything anyone has mentioned or told you.
This is my last communication directed to you on this thread.
I wish you a happy life, but doubt you have the ability to find pleasant pathways.
 

Johnbt

Shiny_Rock
Premium
Joined
Mar 13, 2018
Messages
313
"First, your comment for Kelvin temperature had absolutely no connection with my point so why even to make the effort to answer you?
You should learn what is the SI system"

You brought up temperature and listed the F and C scales to prove part of one of your points. You did not list the Kelvin scale. You should learn more about the SI system. I was entirely on point.

"Celsius is currently a derived unit for temperature in the SI system, kelvin being the base unit."

Let's see...

www.britannica.com/science/International-System-of-Units

"...and for thermodynamic temperature, the kelvin."

Have a pleasant evening.

John
 

Paul-Antwerp

Ideal_Rock
Trade
Joined
Sep 2, 2002
Messages
2,859
This is very interesting Paul.
It could be a suggestion for all super ideal cut diamonds sellers (you and the others) to give an honest opinion on the presence of fluorescence in each diamond because we can't relay on the grading reports.

Hi Stephan,

So, you are asking for our sincere opinion. That is interesting. Why limit it to fluorescence, which in the ranges discussed here, has minimal impact on value? How about our sincere opinion on Color and Clarity?

It could save money, as we would offer our sincere opinion for free, while you now are paying quickly $100.- (more for bigger diamonds) to get the opinion of a lab. And it is not unheard of. At wholesale-level, there is one company selling based upon their own opinion. And at retail-level, Tiffany's is doing the same.

So, what would happen if we would sell diamonds, accompanied by our opinion, not the one of a lab?

Live long,
 

Stephan

Ideal_Rock
Joined
Feb 13, 2003
Messages
2,917
Paul, what I was trying to say: report + opinion.
And yes, not only fluorescence; why not clarity, color and transparency?
You ask what would happen? I guess a gain in consumer trust.
Some diamonds will be priced lower that the report, other will be priced higher, so nothing to lose for you honest dealers?
I'm certainly naive but my question is sincere.
 

OoohShiny

Ideal_Rock
Premium
Joined
Apr 25, 2014
Messages
8,228
Paul, what I was trying to say: report + opinion.
And yes, not only fluorescence; why not clarity, color and transparency?
You ask what would happen? I guess a gain in consumer trust.
Some diamonds will be priced lower that the report, other will be priced higher, so nothing to lose for you honest dealers?
I'm certainly naive but my question is sincere.
I think it's an interesting proposition, but one could argue that it would decrease trust - after all, who should one believe? The grading lab or the vendor? A given vendor (not referring specifically to CBI or their dealer network!) could/would have incentive to 'talk-up' a diamond - so would customers want to pay for the unbiased lab opinion or the potentially biased vendor opinion? Or would both parties be treated with suspicion because they didn't agree with each other?

A tricky situation!
 

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
@Paul-Antwerp
The dimensions on the report are mathematically rounded correct. So this is a fact, not an opinion.
Another question is WHY GIA rounds them. The rounding is matter of opinion.
The plot of inclusions under 10X magnifier is definitely also a fact. The interpretation of inclusion is an opinion.
Similar case was my point, that the fluorescence at 365nm is a fact (yes or no), and should be written as a fact. The level of fluorescence could be subjective so it's an opinion, and the fluorescence impact is clear interpretation.

But for the purpose of this thread, can we go back to the photo I posted. GIA stipulates a fluorescence designation of ‘none’ for that diamond, and others we encounter, while there is clearly some level of fluorescence. How can this be considered factual?

Here I cannot comment because it is not me, making the fluorescence test.
I think I told you, that everybody can speak based on his own life experience and knowledge.
Let people be informed with the FACTS and everybody can make his own conclusion.
I appreciate everybody point of view based on the facts.
I appreciate that you point out on this GIA report fluorescence is presented wrong. May be this is the case and GIA is wrong. This only prove that people have to doubt any lab report and never buy only based on lab report.
As I told you, non of my limited number of diamonds that I personally sent to GIA and that I personally examined prior to sent, non of them returned with different inclusion plot or different fluorescence.
So you have your opinion, I have mine.
 
Last edited:

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
@Garry H (Cut Nut)
Don't get it in a wrong way, I was just making a dispute with you, I don't have bad feelings towards you! I know who you are and I appreciate your knowledge, expert opinion and professional experience is diamonds.
I would like to read more scientific research about fluorescence, because, as you know, this field is still full with blank spots.
 

the_mother_thing

Ideal_Rock
Premium
Joined
Mar 2, 2013
Messages
6,306
So, my point of thinking is, that the buyer should be trustfully informed if the fluorescence is "none" or "some", that's why I do not accept the AGS term "negligible".

I don’t have a dog in this fight, and I’m not wading into the technical, science-y side of things, but I just came across this when checking a GIA report, which made me think of this thread.
FAD1584A-95BD-4C2F-9135-2B629D9DFF0A.jpeg

It would seem GIA’s ‘none’ fluorescence grade isn’t a true ‘zero-zilch-nada’; rather, is also a range that - to me, as a consumer - seems on par with AGS’s ‘negligible’ grade for fluorescence. To me, it seems more transparent to say ‘negligible’ which informs me that there is possibly some minute level of flouro that I can have further inspected if it matters to me vs. saying ‘none’ and there actually maybe being some.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
I don’t have a dog in this fight, and I’m not wading into the technical, science-y side of things, but I just came across this when checking a GIA report, which made me think of this thread.
FAD1584A-95BD-4C2F-9135-2B629D9DFF0A.jpeg

It would seem GIA’s ‘none’ fluorescence grade isn’t a true ‘zero-zilch-nada’; rather, is also a range that - to me, as a consumer - seems on par with AGS’s ‘negligible’ grade for fluorescence. To me, it seems more transparent to say ‘negligible’ which informs me that there is possibly some minute level of flouro that I can have further inspected if it matters to me vs. saying ‘none’ and there actually maybe being some.
Perhaps the takeaway is: In gemology not everything is black and white - especially under a black light. :D
 

EvaEvans

Shiny_Rock
Premium
Joined
Jan 15, 2013
Messages
462
It would seem GIA’s ‘none’ fluorescence grade isn’t a true ‘zero-zilch-nada’; rather, is also a range that - to me, as a consumer - seems on par with AGS’s ‘negligible’ grade for fluorescence. To me, it seems more transparent to say ‘negligible’ which informs me that there is possibly some minute level of flouro that I can have further inspected if it matters to me vs. saying ‘none’ and there actually maybe being some.
It is obvious, that from None to Very Faint is only ONE step of GIA scale.
This is the same if you go to a medical laboratory for making a blood exam. If, for example, your result is <5, then your result is read as Negative. In other case the border could be <30, <0.1, depends of the acceptable accuracy of the specific examination.
It is a question of acceptable accuracy and certain precision, which is specific for every exam. You cannot expect from the grocery store scale the same precision as from the laboratory scale.
However, if the AGS "negligible" means none, faint and up to medium (really?), so the AGS measuring of fluorescence is highly inaccurate.
The AGS fluorescence accuracy I can compare to the grocery store scale.
 
Be a part of the community Get 3 HCA Results
Top