Find your diamond
Find your jewelry
shape
carat
color
clarity

Should we discourage or recommend FL stones?

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
1-1.01ct D VVS1 None 145 stones avg $10,697
1-1.01ct D VVS1 Med 48 stones avg $7,672
1-1.01ct F VVS1 None 223 stones avg $8,350

So fear and ignorance are at play.
Fear of a color drop.
Fear of milky hazy (which is a result of the combination of some types of inclusions and blue fluorescence).

There is no way you can get a 2 color drop in a medium blue fluorescent diamond when you screen out all UV, even wrongly removing near visible violet.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Thanks for posting that Garry- interesting stuff.
It won't affect the bulk of diamond sales which are going to a few companies- none of which invest in diamonds. It’s not like the old days ( 3 years ago) where a larger percentage of new production was sold to dealers, who evaluated each stone.
I don’t see this trend changing.
No matter how well informed PS readers are- many people will just go online, do a bit of googling and go for the safest bet.
A plus for those of us who still might be inclined to actually buy diamonds- and love fluorescent stones.
I don’t foresee the discounts going away anytime soon - no matter what Rapaport says
 

AV_

Ideal_Rock
Joined
Aug 5, 2018
Messages
2,917
@Garry H (Cut Nut) I remember some such from Alrosa picked up by Reuters for all to hear.

@Rockdiamond Yes, this is what I mean. Both procedures of color grading seem perfectly reasonable to me.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Me- I’m doing a post to show it’s raining here in NYC
Bryan- that’s not possible
Me- but I’m getting wet!
Bryan - I’ve got reports and scientific data to show rain is not possible in NYC today
Me- I’m quite sure - I’ve been rained on many times.
Bryan- you’re a science denier. Look at these graphs. And Cowing proved it can’t rain in NYC
Bryan -You’re misleading people and you’re the only one believing in this fairy tale.
Others who are getting wet- WE ARE IN THE RAIN HERE!!!!
Bryan- please explain how that’s possible!!! Can’t happen. I have science to prove it.
Sound familiar Bryan??
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
David, please play nice.
I s the joke in your last post, and it is very funny.
But some will take it the wrong way (Although I think Bryan will get a giggle),

No matter how well informed PS readers are- many people will just go online, do a bit of googling and go for the safest bet.
This statement is so very true. And while there are so many really well meaning and smart savvy folk contribute here on PriceScope and guide people in buying and selecting a top diamond, there is a huge problem.
1. Less than 1% of visitors ever sign up and post.
2. The advice we give here is so very often way over the top and complex for non rocket scientist woman/man in the street.
3. Many your people in love and worried about making the life time commitment choice and working long hours etc in their new career just want to make a simple OK selection. They may not have time to learn our jargon or the desire to spend scarce spare brain power.

We can be way too elitist.

So I have digressed, but if anyone wants to start a thread - let me know. I think we could help 50 times more people get a good enough diamond and setting at a considerable saving without getting 'enchanted' out of their money.
 

OoohShiny

Ideal_Rock
Premium
Joined
Apr 25, 2014
Messages
6,699
This statement is so very true. And while there are so many really well meaning and smart savvy folk contribute here on PriceScope and guide people in buying and selecting a top diamond, there is a huge problem.
1. Less than 1% of visitors ever sign up and post.
2. The advice we give here is so very often way over the top and complex for non rocket scientist woman/man in the street.
3. Many your people in love and worried about making the life time commitment choice and working long hours etc in their new career just want to make a simple OK selection. They may not have time to learn our jargon or the desire to spend scarce spare brain power.

We can be way too elitist.

So I have digressed, but if anyone wants to start a thread - let me know. I think we could help 50 times more people get a good enough diamond and setting at a considerable saving without getting 'enchanted' out of their money.
This is an interesting topic of thought.

Is it possible to simplify and/or distill the important technicalities into a "Newbies' guide to buying a diamond"?

Or is there just too much technical detail behind what we put forward as 'ideal' choices to allow us to simplify it?


I have been pondering the idea of a Flowchart, where a 'newbie' enters at the top, follows the flowchart through, and arrives at a recommendation on what to look for (and perhaps a link through to the PS Search tool with results that are in line with their preferences, which would enable them to look through options immediately).

The flowchart could have a 'Simple' path, but then have a 'Technical' box (link to webpage(s)?) off to one side, whereby the explanations for how recommendations are made is covered in Geek levels of detail.

I have knocked this up quickly - I am sure I have missed things but I thought I'd throw it out there for some views!

Flowchart v0.1.jpg

(There is nothing really on the technical aspects of cut, but then we are taking it as given that we are not compromising on that aspect - perhaps we should have a box for that as well?)
 
Last edited:

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,098
Me- I’m doing a post to show it’s raining here in NYC
Bryan- that’s not possible
Me- but I’m getting wet!
Bryan - I’ve got reports and scientific data to show rain is not possible in NYC today
Me- I’m quite sure - I’ve been rained on many times.
Bryan- you’re a science denier. Look at these graphs. And Cowing proved it can’t rain in NYC
Bryan -You’re misleading people and you’re the only one believing in this fairy tale.
Others who are getting wet- WE ARE IN THE RAIN HERE!!!!
Bryan- please explain how that’s possible!!! Can’t happen. I have science to prove it.
Sound familiar Bryan??

Stay Classy Rockdiamond!

Ron burgundy.png
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Respect is truly a two way street sir. Please acknowledge my experience and contribution- as I do for yours. Then we can actually discuss and exchange ideas to all the readers benefit.
You don’t see any color improvement possible indoors, out of direct sunlight - you’ve obviously never seen it.
I have seen it- for over 40 years and on many occasions. No amount of referring to graphs or studies is going to change what I’ve seen with my own two eyes.
If you could acknowledge this inconsistency we can explore it.
Stay classy. To use your words.

Or just ignore what I’m saying as you have been.
 

TODiamonds

Shiny_Rock
Joined
Jul 27, 2019
Messages
260
Respect is truly a two way street sir. Please acknowledge my experience and contribution- as I do for yours. Then we can actually discuss and exchange ideas to all the readers benefit.
You don’t see any color improvement possible indoors, out of direct sunlight - you’ve obviously never seen it.
I have seen it- for over 40 years and on many occasions. No amount of referring to graphs or studies is going to change what I’ve seen with my own two eyes.
If you could acknowledge this inconsistency we can explore it.
Stay classy. To use your words.

Or just ignore what I’m saying as you have been.
Dude... let it go. Why is it so important that he acknowledge you? He's just another dude on the internet like you are. Forget it and move on with your life.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Hey @TODiamonds
There’s quite a few dudes and ladies who participate here. Bryan and I are both tradespeople. So both He and I are slightly in a different category than many other dudes or dude-ettes Participating.

I participate for many reasons- one of the prime reasons is to educate consumers.
Garry recently started a thread about how this forum gives advice.
To me, a thread like this is vital if education is the goal

I started this thread after a consumer question about fluorescence- and I sensed a shortfall in info on this subject.
Clearly there’s debate among tradespeople- in itself that makes it more interesting to read/discuss.
Some of the differences tradespeople express will never be “settled” because things like assessment of cut has a large component of individual taste.

This particular discussion involves things that are physical realities as opposed to taste based questions. Maybe that’s why both of us are passionate about it.
 

Venzen007

Shiny_Rock
Joined
Dec 22, 2008
Messages
209
I've come to think of floro along the same lines as genetic mutation.

Genetic mutation, itself, is neither good nor bad. Sometimes the mutation has a negative effect on fitness. Sometimes it has a beneficial effect, and still other times it has a null effect (meaning it basically does nothing at all).

I see floro in diamonds the same way. We just have to see for ourselves whether the floro's effect is null, negative, or beneficial.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
I've come to think of floro along the same lines as genetic mutation.

Genetic mutation, itself, is neither good nor bad. Sometimes the mutation has a negative effect on fitness. Sometimes it has a beneficial effect, and still other times it has a null effect (meaning it basically does nothing at all).

I see floro in diamonds the same way. We just have to see for ourselves whether the floro's effect is null, negative, or beneficial.
That is an awesome analogy. Garry has said that it’s never the fluorescence itself that causes the bad for stones to be dull- rather it’s imperfections combined with fluorescence. My experience is that I’ve seen dull fl stones that didn’t have noticeable imperfections- but in fairness I wasn’t looking with this topic in mind.
The “mutation “ analogy lines up with my thought that the fluorescence itself can cause dullness.
 

Venzen007

Shiny_Rock
Joined
Dec 22, 2008
Messages
209
I'm curious whether a certain stone might be considered a stinker in Nairobi (avg UV index of 11.7) but considered a "gem", so to speak, in the Falkland Islands (avg UV index of 2.3), or maybe vice-versa. Anyone aware of any research on this? This is assuming the intensity of UV has an effect.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
I'm curious whether a certain stone might be considered a stinker in Nairobi (avg UV index of 11.7) but considered a "gem", so to speak, in the Falkland Islands (avg UV index of 2.3), or maybe vice-versa. Anyone aware of any research on this? This is assuming the intensity of UV has an effect.
Interesting Mr V,
I we do get a bit higher it seems than where Bryan lives, and way way higher than where Michael Cowing comes from.
So maybe the whitening effect I see is stronger than those 2?
But David is closer to MC (MS) in NYC. But his office is high up, so maybe he is above the smog (hahaha).
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Really interesting point.
Garry has indeed been to our offices- and seen our windows. During daytime hours- even on cloudy days- the light coming in the windows completely overwhelms the overhead fluorescent lighting.


But I've seen this in so many different places. At Winston, back in the dark ages ( the mid '70's), only women graded diamonds for color- and during the winter they'd leave by 3pm. They would use natural lighting- along with lamps.
The windows were north facing.
I hate grading color in "lab" conditions.
Natural lighting- daylight, by far allows the best look. Never in direct sunlight.

Now that I'm thinking about this......
I've graded color in Ramat Gan, Israel- also in natural lighting- and been surprised at the results when I got back to NYC.
Garry- you've surely graded diamonds on different parts of the globe- have you noticed a difference in color grades you saw on the same diamond in different locations geographically?
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
You're such a great dancer Garry, right around my question:)
Have you noticed a difference in your own color grading when it was done it distant locales- even your master set might look different in Mumbai versus Melbourne
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
You're such a great dancer Garry, right around my question:)
Have you noticed a difference in your own color grading when it was done it distant locales- even your master set might look different in Mumbai versus Melbourne
Not at all David. Because I use my master, and when need be I grab a few GIa certed stones and use them too for colors away from my 2 masters (a high H and a high F).
 

sledge

Ideal_Rock
Premium
Joined
Apr 23, 2018
Messages
4,110
I'm curious whether a certain stone might be considered a stinker in Nairobi (avg UV index of 11.7) but considered a "gem", so to speak, in the Falkland Islands (avg UV index of 2.3), or maybe vice-versa. Anyone aware of any research on this? This is assuming the intensity of UV has an effect.
From everything I've read, the intensity of the UV absolutely has an effect.

One of several articles I've read, but it's simple & to the point:


CaptureGIA.PNG


But the issue is more complex than that. First, let's look at the way the UV index is calculated. A simple definition is:

CaptureUVI.PNG


But as you dive further into the UV index, we learn additional details, including a modifier for how it effects human skin. How does this modifier effect diamond fluorescence? It's very unlikely to have an identical result on skin and diamonds, so this would need corrected to find more meaningful correlation.

CaptureUVIdet.PNG

I do understand and respect where you were going with this. But literally there are so many variables to adjust the UV intensity, some that are within our control but many that aren't. If you were sitting in a deep dark hole in Nairobi or the Falkland Islands, it probably wouldn't matter as that's a CONTROLLED environment. Anything else would likely be up for debate.

And for me, that's the rub. If fluor can activate and whiten a stone to any degree, then it needs to be neutralized at the laboratory when color grading is being assigned. If this is not happening, then consumer confidence erodes as you simply don't know what you are buying so a stone with fluor becomes more risky and consequently trades for less dollars (as it should).

How disappointed would you be if you purchased an I colored stone under the premises of 5, but then learned when your stone didn't have sufficient UV intensity looked like 2, 4 or 6? I can't speak for others, but I would be rather livid.

Screen cap from Cowing Study -- PDF download provided by Bryan, post #86:

CaptureSun4.PNG
 
Last edited:

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Cool post Sledge.
So many aspects of this discussion are truly impossible to pin down.
As an example- not everyone has the ability to distinguish between shades of diamonds. People have widely varying degrees of color sensitivity.
When I was in diamond grading school, at Harry Winston, only women were hired to color grade diamonds. They were thought to have better color sensitivity. (As I write this, I think, boy, I'm old.)
But we could attribute differences in experience people have with their ability to actually see what we're talking about.

I do think the issue of geographic location also adds to the controversy in a small way.
But we really do have two different discussions-
1) is whitening possible in daylight coming through windows?
2) is GIA screwing up color grading due to Fluorescence?

To the first point- GIA complete befuddles this issue with statements like this ( from the GIA paper @sledge posted)
Myth #7: Strong blue diamond fluorescence is bad
FACT: GIA studied the influence of blue fluorescence on the appearance of a diamond under normal viewing conditions. The Institute found that average observers (meant to represent the jewelry buying public) could not consistently discriminate any fluorescence-related effects in the viewing environments most similar to those in which jewelry is purchased and worn.

However, GIA also found that strong blue diamond fluorescence could be beneficial. The results of its study revealed that, as noted for Myth #4, some strongly blue fluorescent diamonds were perceived to have a better color appearance than their color grade would suggest when viewed table-up, with no discernible trend table-down.



Am I missing something or does the statement in red directly contradict the statement that directly follows, in blue?

To the second point- Color grading is not, and never will be an exact science.
 

sledge

Ideal_Rock
Premium
Joined
Apr 23, 2018
Messages
4,110
Am I missing something or does the statement in red directly contradict the statement that directly follows, in blue?

To the second point- Color grading is not, and never will be an exact science.
Thanks @Rockdiamond. :cool2:

I'm glad you asked -- because I was about to bust your chops. :lol:

Yes, it's in direct conflict. Shame on GIA for publishing that data. You can't say most people can't see a difference and then turn around and say some prefer strong blue.

Makes me feel bad for even posting that GIA web link as a reference point now. However, the Cowing report also eludes to the same point in GIA myth #3 that I originally referenced it for -- intensity matters.

And never say never. Technology changes all the time. Although, yes, the current situation is that color (and clarity) grading is done by humans, and no matter how great we are -- we are still flawed and make mistakes.

What annoys me is that GIA has taken steps to reduce, but not eliminate UV in color grading. Thanks for half fixing the problem. :roll:

My guess is this is to save face with dealers and protect values of stones already graded/sold and that are in the current marketplace. Just as I feel that is the reason they will never change their (IMO, weak) "excellent" line of cut grading.

FWIW, I was only half joking about buying HRD.


CaptureGIAgrading.PNG
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
I so much appreciate your intellect and willingness to explore @sledge !!
Personally, I feel the Cowing paper has too much baggage to be really useful. The incorrect suppositions call the conclusions into doubt.

And it would be so amazing if we could all agree that the science on this is not settled, by any means. That would allow open discussion.

And never say never. Technology changes all the time. Although, yes, the current situation is that color (and clarity) grading is done by humans, and no matter how great we are -- we are still flawed and make mistakes.
Color grading can be done by machine. Ronnie Winston started working on that way back in 1977. Much progress has been made in machinery to color grade diamonds.
The quandy still won't go away.
There's the method GIA uses- grading through the pavilion. Many times the face up and pavilion views are different colors.
It's never going to be an exact science- even if we graded through the table. Simly due to differences in the way each diamond uses light.
People are sometimes very concerned about making sure Pavé halo diamonds match the center stone.
Well, if the center stone is a pear shape ( or whatever) there's really no way to match exactly- complimentary, yes!
Exact match?
No.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
Thanks @Rockdiamond. :cool2:

I'm glad you asked -- because I was about to bust your chops. :lol:

Yes, it's in direct conflict. Shame on GIA for publishing that data. You can't say most people can't see a difference and then turn around and say some prefer strong blue.

Makes me feel bad for even posting that GIA web link as a reference point now. However, the Cowing report also eludes to the same point in GIA myth #3 that I originally referenced it for -- intensity matters.

And never say never. Technology changes all the time. Although, yes, the current situation is that color (and clarity) grading is done by humans, and no matter how great we are -- we are still flawed and make mistakes.

What annoys me is that GIA has taken steps to reduce, but not eliminate UV in color grading. Thanks for half fixing the problem. :roll:

My guess is this is to save face with dealers and protect values of stones already graded/sold and that are in the current marketplace. Just as I feel that is the reason they will never change their (IMO, weak) "excellent" line of cut grading.

FWIW, I was only half joking about buying HRD.


CaptureGIAgrading.PNG
Hi Sledge,
Rapaport Research division published an article last week. They gave me a copy but not to be shared (it costs $1,000 subscription).
Since 2018 GIA have been using instruments to grade UV for consistency.
They are working on a system "to measure the impact of fluorescence on appearance".

The 1997 study is underwhelming. But at least GIA did some research and applied lighting and grading conditions post 2000 that they believe match CIE Indoor lighting standards.
The 2013 Lou et al study contains info that shows that 280-415nm violet and near visible creates the most whitening effect.
https://www.gia.edu/gems-gemology/summer-2013-luo-fluorescence-optical-defects

Michael Cowing measured the wrong UV with the wrong UV meter.

My question to everyone - can you grade the color of diamonds in low lighting settings?
Can you tell a I from an F?
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Garry- of course the answer is you need lots of light to see the remarkably subtle differences between the shades. How about you Garry- do you prefer to color grade in daylight or a controlled lab environment?
I ask because from my perspective even if I graded the color of a diamond in a dark room under a lamp, I’d still want to look at it in daylight.
Color grading is tricky, to say the least.
I don’t know that any amount of research or standardized or improved lighting can create a color grading system that’s not made “wonky” by the characteristics of the diamonds themselves.
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,772
I don’t know that any amount of research or standardized or improved lighting can create a color grading system that’s not made “wonky” by the characteristics of the diamonds themselves.
And the studies are to small to show if the wonk is not the norm.
A really comprehensive study would be a massive undertaking and cost a boatload of money which no one wants to put up.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,783
And the studies are to small to show if the wonk is not the norm.
A really comprehensive study would be a massive undertaking and cost a boatload of money which no one wants to put up.
I have been playing with a G strong and an E none, both carat stones. It is very hard to do a proper study even with just a pair.
1 metre (3ft) from a window on a cloudy day at 1.20pm they both look nice colors.
Cropped but otherwise undoctored.

1575512936196.png
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
7,987
Great start Garry!
I've been thinking of how to illustrate this best.
I will be looking for means ( stones that have the characteristics) of doing so next week
 

novichok

Rough_Rock
Joined
Dec 5, 2019
Messages
6
My educational background is chemistry and because of that I find diamonds with fluorescence very interesting. I am a newbie when it comes to diamonds and can't really understand the reasoning behind people suggesting against fluorescence. Ok, too much fluorescence might give a diamond a cloudy look but that is not always the case. It is like saying too much sugar is not good for you so how about you stop eating any amount of sugar.
 
Be a part of the community It's free, join today!

Need Something Special?

Get a quote from multiple trusted and vetted jewelers.

Holloway Cut Advisor



Diamond Eye Candy

Click to view full-size image.

New posts

Top