A message on Strong UV Fluorescence

[oldminer]

Just wrote the following to a participant in a direct message, but it seemed a good thing to post on the forum:
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Strong fluorescence is generally something an expert''s eyes can detect in regular fluorescent room lighting. It may be anything from slightly noticeable to quite apparent, but there are no true standards used in categorizing the strength and visibility of UV fluorescence. If you can''t detect it, then you won''t be visually bothered. I would suggest examining such a diamond in strong, direct sunlight and see what happens. Do this outside, not behind glass, as UV is filtered out by glass. Then, you may see the effect whiten the stone or make it a bit semi-opaque. Sometimes fluorescence is yellow, green, or orange instead of white or blue. Those rarer colors will definitely create visual changes in direct UV situations.

I wear a very intensely fluorescent diamond every day, so it is not a terrible problem. I like the unusual character it gives the stone, but many would object to it. My stone, though ideal cut, becomes purplish and rather murky when exposed to UV. I have seen very few with a similar response.

Fluorescence makes a diamond a bit to a lot less marketable. Dealers prefer diamonds with little to no UV fluorescence. If you ever want to sell the diamond it means fewer dealers will be strong bidders. It is a haggling point and dealers love to haggle.

 

[RockDoc]

I agree with Dave, but thought I would add this comment to his post.


When looking at a diamond for its fluoresence characteristics, I think folks should make the minor investment in a small piece of Lexan - 1/4 inch thick - maybe 2 inches by 4 inches.

Hold the stone in daylight or lighting with a UV influence, then put the lexan between the stone and the light source. The Lexan will not let UV light though, so you can see the result of the fluoresence very easily.

Lexan can be purchased at any plastics dealer generally, and maybe they will have a piece of scrap Lexan like this and not even charge you for it.

So it''s a handy little tool to have - if you''re curious about fluoresence.

Rockdoc

 

[oldminer]

Great suggestion!!!! Most safety glasses will do the trick.

 

[strmrdr]

The few iv seen that it was visible in I liked it.
Gave a nice blue tint to the diamond that I liked.

 

[ecf8503]

I bought a D color ideal cut diamond with strong blue fluoresence, and I love it. I don''t think the effect is visible, but if it is I like it!

Much has been made of fluoresence, whether it is good, bad or indifferent - and it seems to me that it has received a bum rap for some reason. GIA did a study in 1997 re: fluoresence, and in it they had a hard time finding enough stones that exhibited the much-talked-about, but extremely rarely seen hazy/cloudy/milky/oily effect that everyone seems to be paranoid about. It is a very interesting read. Now that I know more about fluoresence, I wonder how this mis-information / bad reputation started!

Anyway, for those interested, here is the link to the GIA study:

GIA fluoresence study

I posted pics of my ring, in which the vast majority were taken outdoors in unfiltered sunlight. The link to my stone is here

Below is a copy of an exchange within that thread re: fluoresence:



Date: 5/21/2005 10:11:22 AM
Author: SUPA IDEAL KID
Why would you get a D color with Strong blue fluoresence? Didn''t your jeweler advise against it? I am under the impression when going with such great color grade, avoid strong fluoresence. Ring looks great in the photos!





Thanks for the comments, everyone. To Supa Ideal Kid - I have done a lot of reading about fluoresence in diamonds, and I would suggest you read this article from GIA regarding it. http://www.gia.edu/pdfs/W97_fluoresce.pdf

It is an unfortunate misconception that fluoresence is a bad thing - it didn''t used to be. In fact, there are periods of time in which these "blue-white" diamonds, as they were referred to, were in very high demand. But times change...

Jonathan from GOG and Barry from Superbcert have really opened my mind and my eyes about fluoresence. The concern over strong and very strong fluoresence in stones is that it has the potential to make a stone look hazy / milky / oily in direct sunlight. However, this is not a given - not all stones do this - in fact, if you read the GIA study, you will find they mention that they had a hard time finding enough stones with strong or very strong fluoresence that exhibited this property at all.

I think I explained my reasons for choosing a stone with strong blue fluoresence in my original post. Let me put it this way - if this stone had no fluoresence, I still would have purchased it - the fluoresence is a neutral to positive aspect to me now. As I said, I too was hesitant about / concerned about the fluoresence - until I saw one with my own eyes. THAT is what really matters.

I found some local jewelers that tried to discourage me from fluoresence, and after educating myself I determined that those people really need to read that GIA study! These are the same people who tried to tell me that a GIA Excellent / Excellent is an ideal cut stone, most of them feigned ignorance (or maybe they really didn''t know) about Sarin / Megascope reports, Brilliancescopes, Ideal / Firescopes, etc.

Bottom line is when purchasing a stone, your eyes will tell you the truth. If when I received this stone I was not happy, I would have sent it back. No risk. But I didn''t notice / liked the fluoresence. It was never a negative for me, even though I was at some point in my pre diamond education days a bit hesitant about it for the same reasons you mentioned above. Live and learn... and then buy a fluorescent diamond!

 

[glitterata]

Dave--

I don''t suppose you have any photographs you could post that show your diamond''s haziness? I would love to see that. Does it show up in photos?

 

[kenny]

Great insight RocDoc

BTW I use Lexan all the time because of its UV-blocking properties.
I am an artist who paints in watercolor, which UV light fades over time.
So during framing we use Lexan instead of glass.
Looks the same.

BTW Lexan is directional.
One particular side is designed to face the offending light source, and the other side faces the art.
You can only tell which side is which by reading the writing on the coating before you peel it off.
After you peel, there is no way to tell.

I only mention this because I'm not sure if it attenuates UV equally in both directions, I would guess not.
Perhaps it does work to a lesser degree in the wrong direction.

I am going to take a piece and make a little scratch on the corner of the side that faces the sun, BEFORE I peel the backing off of both sides.

 

[oldminer]

I may be able to add with and without UV photos tomorrow when I am in the lab. We''ll see how it shows up. I have not tried to make it visible in a photo before.