Is blue the only color for fluorescence?

[ButterBean]

Is blue the only color for fluorescence? In comparing a number of stones, when I see "medium blue" and "medium" but no color indicated, does it mean the same thing?
BB

 

[Indira-London]

Blue is not the only colour of fluorescence - it is merely the most common colour. "Medium" or "Faint" or "Stong" indicates the strength of fluorescence.

See the link below for a GIA study on fluorescence which explains more about fluorescence.
http://lgdl.gia.edu/pdfs/W97_fluoresce.pdf

Here is a summary from that study
"Some gem diamonds fluoresce, most commonly blue, to the concentrated long-wave ultraviolet radiation of a UV lamp. There is a perception in the trade that this fluorescence has a negative effect on the overall appearance of such a diamond. Visual observation experiments were conducted to study this relationship. Four sets of very similar round brilliant diamonds, covering the color range from colorless to faint yellow, were selected for the different commonly encountered strengths of blue fluorescence they represented. These diamonds were then observed by trained graders, trade professionals, and average observers in various stone positions and lighting environments. For the average observer, meant to represent the jewelry buying public, no systematic effects of fluorescence were detected. Even the experienced observers did not consistently agree on the effects of fluorescence from one stone to the next. In general, the results revealed that strongly blue fluorescent diamonds were perceived to have a better color appearance when viewed table-up, with no discernible trend table-down. Most observers saw no relationship between fluorescence and transparency."

For those who like to know details - here is more details about what causes the different colours!

"Gem diamonds typically contain a variety of structural
defects, most involving impurity atoms such as
nitrogen, hydrogen, and boron. Nitrogen-related defects
are the most common of these, and only some of the
resulting defects cause luminescence (Clark et al.,
1992; Collins, 1992; see also Davies et al., 197. The
nitrogen-related defects, and their association with fluorescence,
are described as follows:
• A single nitrogen atom substituting for carbon in a
diamond that is partly type Ib (see, e.g., Fritsch and
Scarratt, 1992) produces orangy yellow fluorescence.
• A group of two nitrogen atoms, the A aggregate, tends
to quench—that is, extinguish—fluorescence.
• A group of three nitrogen atoms is called the N3 center,
and produces blue fluorescence.
• A group of four nitrogen atoms is called the B aggregate,
and is not known to cause luminescence.
• A lens-shaped cluster of nitrogen atoms is called a
platelet, and is associated with yellow fluorescence.
• A single nitrogen atom trapped near a carbon vacancy
causes bright orange fluorescence.
• A vacancy trapped near an A or B aggregate is called
the H3 (H4) center, and generates green fluorescence.

A single diamond may contain several different
kinds of defects, leading to a range of complex relationships
between nitrogen content, nitrogen aggregation
state, diamond color, and fluorescence color and
strength. A diamond may also display two different fluorescence
colors, either clearly zoned or closely mixed
together. As described in the Background section of the
text, of 5,710 colorless to near-colorless diamonds that
fluoresced a noticeable color, 97% showed blue fluorescence,
which is caused by the N3 center. Of 16,835 diamonds
in the same study that did not fluoresce, many
contained N3 centers, but they also contained enough
A aggregates to prevent any visible luminescence. The
existence of N3 centers in these diamonds is suggested
by their yellow bodycolor (most commonly caused by
“Cape” absorption bands, which are related to these
centers); the existence of A aggregates (or other centers
that quench luminescence) is evident from the fact that
the stones do not fluoresce. These complexities confound
the trade notion that nonfluorescent
diamonds are more “pure” than those that
fluoresce, since there are nitrogen-related
centers that extinguish fluorescence, as
well as those that cause blue fluorescence

 

[ButterBean]

WOW, Thanks! That''s more info than I even hoped for. So, would you then assume that if a stone is graded to have some flouro, but NO color is indicated, it would be blue?

Date: 7/24/2008 8:26:51 AM
Author: Indira-London

Blue is not the only colour of fluorescence - it is merely the most common colour. ''Medium'' or ''Faint'' or ''Stong'' indicates the strength of fluorescence.

See the link below for a GIA study on fluorescence which explains more about fluorescence.
http://lgdl.gia.edu/pdfs/W97_fluoresce.pdf

Here is a summary from that study
''Some gem diamonds fluoresce, most commonly blue, to the concentrated long-wave ultraviolet radiation of a UV lamp. There is a perception in the trade that this fluorescence has a negative effect on the overall appearance of such a diamond. Visual observation experiments were conducted to study this relationship. Four sets of very similar round brilliant diamonds, covering the color range from colorless to faint yellow, were selected for the different commonly encountered strengths of blue fluorescence they represented. These diamonds were then observed by trained graders, trade professionals, and average observers in various stone positions and lighting environments. For the average observer, meant to represent the jewelry buying public, no systematic effects of fluorescence were detected. Even the experienced observers did not consistently agree on the effects of fluorescence from one stone to the next. In general, the results revealed that strongly blue fluorescent diamonds were perceived to have a better color appearance when viewed table-up, with no discernible trend table-down. Most observers saw no relationship between fluorescence and transparency.''

For those who like to know details - here is more details about what causes the different colours!

''Gem diamonds typically contain a variety of structural
defects, most involving impurity atoms such as
nitrogen, hydrogen, and boron. Nitrogen-related defects
are the most common of these, and only some of the
resulting defects cause luminescence (Clark et al.,
1992; Collins, 1992; see also Davies et al., 197. The
nitrogen-related defects, and their association with fluorescence,
are described as follows:
• A single nitrogen atom substituting for carbon in a
diamond that is partly type Ib (see, e.g., Fritsch and
Scarratt, 1992) produces orangy yellow fluorescence.
• A group of two nitrogen atoms, the A aggregate, tends
to quench—that is, extinguish—fluorescence.
• A group of three nitrogen atoms is called the N3 center,
and produces blue fluorescence.
• A group of four nitrogen atoms is called the B aggregate,
and is not known to cause luminescence.
• A lens-shaped cluster of nitrogen atoms is called a
platelet, and is associated with yellow fluorescence.
• A single nitrogen atom trapped near a carbon vacancy
causes bright orange fluorescence.
• A vacancy trapped near an A or B aggregate is called
the H3 (H4) center, and generates green fluorescence.

A single diamond may contain several different
kinds of defects, leading to a range of complex relationships
between nitrogen content, nitrogen aggregation
state, diamond color, and fluorescence color and
strength. A diamond may also display two different fluorescence
colors, either clearly zoned or closely mixed
together. As described in the Background section of the
text, of 5,710 colorless to near-colorless diamonds that
fluoresced a noticeable color, 97% showed blue fluorescence,
which is caused by the N3 center. Of 16,835 diamonds
in the same study that did not fluoresce, many
contained N3 centers, but they also contained enough
A aggregates to prevent any visible luminescence. The
existence of N3 centers in these diamonds is suggested
by their yellow bodycolor (most commonly caused by
“Cape” absorption bands, which are related to these
centers); the existence of A aggregates (or other centers
that quench luminescence) is evident from the fact that
the stones do not fluoresce. These complexities confound
the trade notion that nonfluorescent
diamonds are more “pure” than those that
fluoresce, since there are nitrogen-related
centers that extinguish fluorescence, as
well as those that cause blue fluorescence

 

[WinkHPD]

Date: 7/24/2008 10:49:52 AM
Author: ButterBean
WOW, Thanks! That''s more info than I even hoped for. So, would you then assume that if a stone is graded to have some flouro, but NO color is indicated, it would be blue?

That is correct, if the color is not mentioned it is always blue. I have a treated blue with a garrish yellow fluorescence in a ring that I wear, looks horrible out of doors, but I have always enjoyed wearing it.

Wink

 

[WinkHPD]

P.S. Indira''s post had a LOT of excellent and pertinent information.

 

[Indira-London]

Thank you - glad to have helped. I had hoped I was not over the top on info - I am afraid that as a chemist, I find all these details fascinating!

 

[LD]

A few weeks ago I had fun taking some photos of fluoresence. Here''s a strong blue:

 

[LD]

Here''s one that looks either yellow or green (probably more green) - I can''t make up my mind!

 

[glitterata]

Just for fun a few months back, I bought a .27 ct R color SI2 transition cut diamond on ebay, for something like $40. The seller did the grading; I have no idea how accurate the color grade is, but I''m inclined to trust it because, really, when you get that low, which direction would you lie in? Make it sound whiter than it really is? Make it sound closer to fancy yellow than it really is? And is the price difference between, say, a .27 R and a .27 T enough to make the lie worth telling? Anyway, the point is, the thing fluoresces yellow. It''s adorable. The seller didn''t make any note of the fluorescence, perhaps because yellow fluo is supposed to be the kiss of death. But to me it makes the diamond that much more fun. (Of course, if it were a big, expensive stone, I might feel differently.)

 

[Circe]

LovingDiamonds, those are fantastic photos! How on earth did you achieve the effect of the first one? The stone''s the only bit to look as though it''s under the black light! I *wish* I could take such clear fluorescence shots: mine always look a little washed out from the blacklight ....

 

[ButterBean]

Date: 7/24/2008 10:54:39 AM
Author: Wink

Date: 7/24/2008 10:49:52 AM
Author: ButterBean
WOW, Thanks! That''s more info than I even hoped for. So, would you then assume that if a stone is graded to have some flouro, but NO color is indicated, it would be blue?

That is correct, if the color is not mentioned it is always blue. I have a treated blue with a garrish yellow fluorescence in a ring that I wear, looks horrible out of doors, but I have always enjoyed wearing it.

Wink

Thanks for your video on fluoro I found in the archives of "Wink TV" - I watched it this morning. Why have you stopped doing those, if I can ask? If you decide to start up again, I would tune in ... VERY good information!
BB

 

[Garry H (Cut Nut)]

In addition to all the lovely info - GIA found in 1997 study that less than 1% of diamonds they studied had fluoro other than blue

 

[ButterBean]

Really? So, if I was in the market for a fancy yellow (which I''m not) but happened to find one with either yellow or green fluoro, it would probably make for an AMAZING show!

 

[Fly Girl]

Here is a shot of the fluor of my 1.5 F VS2 with medium blue fluor. The side stones are irradiated yellows, and the flur ranges from strong green to lighter green and orange. The earrings are both graded by the GIA as faint blue fluor.

The strong green color on the one side is very noticable in sunlight, changing the yellow side stones to more of a green color. A fussy person probably wouldn''t like the effect, but I think it is incredibly cool and wouldn''t change a thing.

I posted shots of my ring in daylight here, along with sunlight and another photo under the UV light. Link There are also photos of my chameleon diamond which has so much green fluor, it simply glows in the sunlight.

 

[ButterBean]

Flygirl, that''s wonderful! Your little green pear is positively JUICY! Makes me think there may be one with my name on it down the road. But first ... Could I ask for more pics of your Ering stone, too? I would love to see what the medium blue looks like in all different lighting ... please? I do believe that mb is for me.

Thanks! BB

 

[LD]

Date: 7/24/2008 6:14:37 PM
Author: Circe
LovingDiamonds, those are fantastic photos! How on earth did you achieve the effect of the first one? The stone''s the only bit to look as though it''s under the black light! I *wish* I could take such clear fluorescence shots: mine always look a little washed out from the blacklight ....

Thank you Circe. The diamond has a very strong fluor which I think helps! All I did was put a UV pen light in front of the ring and then took the picture one evening under low electric light. I''m not sure but it might be that I wasn''t in a completely dark room? Not sure though! Hope this helps.

 

[ButterBean]

Lovingdiamonds, You are quite a photographer! Do you have any of your stone in sunlight or shade or cloudy day? I am very interested in all the different looks of these unique diamonds. Your is spectacular.
BB

 

[coatimundi_org]

*just to add for fun*
The Hope diamond fluoresces red--here's a photo.
It it is also phosphorescent.

The photo is from this article:
http://www.geotimes.org/jan08/article.html?id=WebExtra011108.html

I love fluorescence!

 

[ButterBean]

Coatimundi, Thanks for sharing that! I have never seen that photo before, or actually of red like that. Does your ering stone have fluor? The one in your avatar looks quite nice.
BB

 

[coatimundi_org]

You''re welcome! Fun topic--thanks for posting!

I wish my rings had fluor, but neither do--bummer for me! My next stone certainly will.

 

[glitterata]

Gotta love the Hope Diamond.

 

[Fly Girl]

Date: 8/1/2008 5:18:44 PM
Author: ButterBean
Flygirl, that''s wonderful! Your little green pear is positively JUICY! Makes me think there may be one with my name on it down the road. But first ... Could I ask for more pics of your Ering stone, too? I would love to see what the medium blue looks like in all different lighting ... please? I do believe that mb is for me.

Thanks! BB

Thank you, ButterBean! Yes, that little green pear is my color change diamond. I love color change stones, and it is so amazing to wear. The color changes quite readily in different lighting situations.

There are more pictures of my e-ring center stone here. Link There may be some fluor effect in the indoor shot with the sunlight hitting the diamond from behind. Most of the time, though, you won''t see any effect from medium blue fluor.

 

[DiamondExpert]

I have found that GIA does not always indicate fluor color - stone on left is faint flour on cert, but yellow not indicated...the other stones, in sequence are med blue and faint blue...disregard reflections of UV bulb.

 

[ButterBean]

Thanks, diamondexpert. I don''t suppose you might have a comparison like that where they were in sun??
I guess I''m wondering what a stone with blue flour will look like, especially out in the sun. I have read where a few posters have said it turns a light blue, or lavender blue color. I would love to see what it looks like. The only stone with flour I have personally seen was at a local b&m. It was very cloudy and unattractive. So, although the black light effect is a novelty for sure, I am too old for nightclubbing, but WILL be out in the sun often.
BB

 

[arjunajane]

Date: 8/4/2008 9:22:11 AM
Author: ButterBean
Thanks, diamondexpert. I don't suppose you might have a comparison like that where they were in sun??
I guess I'm wondering what a stone with blue flour will look like, especially out in the sun. I have read where a few posters have said it turns a light blue, or lavender blue color. I would love to see what it looks like. The only stone with flour I have personally seen was at a local b&m. It was very cloudy and unattractive. So, although the black light effect is a novelty for sure, I am too old for nightclubbing, but WILL be out in the sun often.
BB

Hey butterbean.
Like you, many PS'ers are keen on the idea of fluor in their stones - after all, its really just another fun aspect to have in your stone!

This may not be the best example, but here's a pic of my AGS med fluor in direct sunlight. As you mentioned, it turns a violet-ish colour.
The stone that you mentioned at your local B&M is definately not the norm as far as PS-vendors and fluor stones go. I have never seen a pic of an oily/hazy stone, but I understand they are actually quite a rare occurence.

There are many similiar pics of fluoro in sunlight in the SMTR threads if you are interested.

 

[Ellen]

Love all these flo shots! Here is vivian''s M color stone with SB.

 

[glitterata]

It''s important not to confuse the effects of the fluorescence with simple reflections of the blue sky. Any diamond will reflect the blue sky. In my (limited) experience, fluorescence shows up as a more purply glow, not the pale blue of the reflected daytime sky. Perhaps someone with a strong blue fluorescent diamond and one the same color but without fluorescence can take a picture of them side by side in daylight?

 

[Lorelei]

Date: 8/4/2008 12:19:35 PM
Author: glitterata
It's important not to confuse the effects of the fluorescence with simple reflections of the blue sky. Any diamond will reflect the blue sky. In my (limited) experience, fluorescence shows up as a more purply glow, not the pale blue of the reflected daytime sky. Perhaps someone with a strong blue fluorescent diamond and one the same color but without fluorescence can take a picture of them side by side in daylight?

Here is a pic which shows that from PSer Belle. The diamond below has no fluorescence.

 

[Ellen]

Date: 8/4/2008 12:19:35 PM
Author: glitterata
It''s important not to confuse the effects of the fluorescence with simple reflections of the blue sky. Any diamond will reflect the blue sky. In my (limited) experience, fluorescence shows up as a more purply glow, not the pale blue of the reflected daytime sky. Perhaps someone with a strong blue fluorescent diamond and one the same color but without fluorescence can take a picture of them side by side in daylight?

I have a pair of studs I bought pre-PS that I''ve just thrown in the US. They are "supposed" to both be G (no certs, and I know now I got ripped off on the clarity, but they do seem the same color). One has SB and one doesn''t. If I can get some good shots I''ll post them.

 

[Ellen]

So I took some shots of the studs today, and it proved interesting. I know the one is SB, as the IA verified it after putting it in the box, but try as I might, I couldn't really get it to show up much. That may go back to those threads on the location of the flo. This stones appearance is also affected by it, it's pretty easy to tell which is which, because the flo stone appears foggy/hazy. So it can be educational in that respect, this is NOT what you want your flo stone to look like!

I did not have an actual appraisal done on these, I mainly took them in with my upgrade, to see if the clarity was what I thought they looked like (SI2), which was confirmed. So they are supposed to both be G, but it's not been verified.

To be honest, I really didn't take as many as I normally would have, the heat index was 117, just a tad warm out there in the blazing sun.

First one shows more than any of the others. (flo on right)