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Transparency in diamonds vs. strong fluorescence

gailforcewinds

Rough_Rock
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Jun 27, 2011
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6
I have read a lot about strong fluorescence in diamonds giving a milky or cloudy appearance to diamonds, but I think often a simply cloudy diamond gets mistaken for being highly fluorescent. I included a photo of a Round Brilliant diamond that looks good in most lighting, however very milky/hazy in jewelry store spot lighting or direct sunlight. It rates a 1.3 on HCA and is an SI2 in clarity, but lacks transparency most likely do to pin point inclusions scattered throughout... Therefore giving in a lifeless dull look in certain light. My first impression was that it was an overly fluorescent stone but actually shoes no long wave or short wave fluorescence. (I'm a fan of blue fluorescence in diamonds- You can see in this photo that the strong blue fluorescence of my oval doesn't impair the transparency of the diamond in sunlight)
The center diamonds in the photos are a follows: 2.65 Oval (F color) with strong blue fluorescence, 2.31 Rd (H color) No fluorescence, 1.35 Rd (G color) No fluorescence.

IMGP1500.JPG
 

kenny

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I believe I've read many times here that it is possible, but very rare, for strong florescence to cause the milky-oily look in sunlight.

Yes a cloud can do cause a milky look too but that's a different phenomenon.
I'm sure if a cloud was the cause of that rare florescence milkiness phenomenon GIA and others would have caught it.

Showing a pic of a strong-fluor diamond, which like most others does not have the milkiness, next to a non-fluor diamond with milky appearance from a cloud proves nothing.
 

oldminer

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Your three diamonds are an interesting demonstration of what often happens. There are many degrees of imperfection which create cloudy appearance to a greater or far lesser extent. There are some UV fluorescent diamonds which react to some light in the more visible spectrum or in the shorter wavelength of UV than others which react to LWUV and will show more or less transparency when giving off their fluorescent reaction. Sometimes a strongly reactive fluorescent stone may appear cloudy diamond, but your demo shows it may not always happen.
 

gailforcewinds

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Yes, exactly. The (middle) round has the look an "over-blue" might have in direct sunlight, but instead the milkiness is NOT caused by fluorescence as you might first suspect. Instead it's a transparency issue.
I've just seen a few posts from pricescope members concerning strong fluorescence (and wondering about it being the cause of their diamonds having a hazy appearance in spot lighting/ sunlight) Several people I showed this RB to assumed it to be very strongly fluorescent because of the "eye-clean" clarity grade and high color. Clouds and twinning wisps, structural phenomena such as graining are usually noted on certs, but not always. I just know at times strong fluorescence gets a bad rep and seems to be discussed more often than transparency of a diamond. I've seen a few VS2 and SI1 diamonds with a slightly cloudy appearance but look nearly perfect under the microscope!

I passed on this round diamond because it was slightly cloudy throughout, even though it looked fabulous on paper! (SI2 G excellent cut/spread)
 

gailforcewinds

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kenny said:
I believe I've read many times here that it is possible, but very rare, for strong florescence to cause the milky-oily look in sunlight.

Yes a cloud can do cause a milky look too but that's a different phenomenon.
I'm sure if a cloud was the cause of that rare florescence milkiness phenomenon GIA and others would have caught it.

Showing a pic of a strong-fluor diamond, which like most others does not have the milkiness, next to a non-fluor diamond with milky appearance from a cloud proves nothing.
Kenny,
I think you misinterpreted the focus of my blog :)

-Clouds have nothing to do with the fluorescence in diamonds but occasionally can look visually similar and are mistaken as v. strong fluorescence, is what I was trying to point out. =)

I've had a couple customers ask me to check their diamonds for fluorescence because of their visual appearance (and what they read about the oily/milky look of over blues), in which end up being due to transparency issues not to fluorescence.
 

CaprineSun

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Sep 30, 2010
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547
Interesting.

Would a poorly cut diamond also affect the transparency of the diamond?
 

kenny

Super_Ideal_Rock
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gailforcewinds|1309984913|2963035 said:
Kenny,I think you misinterpreted the focus of my blog :)
Sorry.

Blog?
What blog?
I did not see any link to a blog.
I only saw your post, which included a pic.

A blog is something different.

BTW, are you in the trade?
Your post says so but there is no link to any business in your sigline.
Just curious.
 

yssie

Super_Ideal_Rock
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kenny|1309880343|2961954 said:
I believe I've read many times here that it is possible, but very rare, for strong florescence to cause the milky-oily look in sunlight.

I'm sure if a cloud was the cause of that rare florescence milkiness phenomenon GIA and others would have caught it.

Showing a pic of a strong-fluor diamond, which like most others does not have the milkiness, next to a non-fluor diamond with milky appearance from a cloud proves nothing.

Disagree on this one
GIA's paper http://lgdl.gia.edu/pdfs/W97_fluoresce.pdf is very careful not to attribute fluorescence as the cause of haziness, very strong, strong, or none.
There is a reason for that - they can't say anything with any surety. Yet it seems to be a universal truism... Threads like this that question what the industry as a whole takes as truth without further explanation or detail are invaluable IMO.

In that vein - I completely fail to understand why fluor, which is the same result of the same reactions in all instances, would rarely - but not always - cause certain effects, given otherwise identical circumstances. Obviously the circumstances cannot be otherwise identical. How? Probably a hundred different ways - of which I have no doubt pinpoint clouds are one.
 

stci

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Jan 7, 2007
Messages
2,514
kenny|1309880343|2961954 said:
I believe I've read many times here that it is possible, but very rare, for strong florescence to cause the milky-oily look in sunlight.

Yes a cloud can do cause a milky look too but that's a different phenomenon.
I'm sure if a cloud was the cause of that rare florescence milkiness phenomenon GIA and others would have caught it.

Showing a pic of a strong-fluor diamond, which like most others does not have the milkiness, next to a non-fluor diamond with milky appearance from a cloud proves nothing.
I disagree... it's not rare to see milky diamond because of strong florescence. I know you said it many times (it's rare) but I often see dull diamonds in pictures because of this florescence.
 

slg47

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stci|1310008251|2963389 said:
kenny|1309880343|2961954 said:
I believe I've read many times here that it is possible, but very rare, for strong florescence to cause the milky-oily look in sunlight.

Yes a cloud can do cause a milky look too but that's a different phenomenon.
I'm sure if a cloud was the cause of that rare florescence milkiness phenomenon GIA and others would have caught it.

Showing a pic of a strong-fluor diamond, which like most others does not have the milkiness, next to a non-fluor diamond with milky appearance from a cloud proves nothing.
I disagree... it's not rare to see milky diamond because of strong florescence. I know you said it many times (it's rare) but I often see dull diamonds in pictures because of this florescence.
I don't think you can judge by a picture whether a diamond is dull due to fluorescence or due to some other factor (such as dirt/grime). I wouldn't discount the GIA study.
 

Garry H (Cut Nut)

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I think a larger proportion of high clarity strong (? 10-20% ?) and very strong blue (? 30-40% ?) fluoro diamonds have a haziness or milkyness in shaded daylight. Sadly there is no grading system to identify it.
I also think there is a problem with SI stones with clouds - and they look lousy in all types of light and are a much bigger problem because too many people search for eye clean SI stones and end up with duds.

I dont much care about direct sunlight because most well cut diamonds look lousy in that light anyway.
 

Lula

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Apr 5, 2009
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Garry H (Cut Nut)|1310041171|2963643 said:
I think a larger proportion of high clarity strong (? 10-20% ?) and very strong blue (? 30-40% ?) fluoro diamonds have a haziness or milkyness in shaded daylight. Sadly there is no grading system to identify it.
I also think there is a problem with SI stones with clouds - and they look lousy in all types of light and are a much bigger problem because too many people search for eye clean SI stones and end up with duds.

I dont much care about direct sunlight because most well cut diamonds look lousy in that light anyway.
Yes, I think that clouds are often seen as having minimal effect on a diamond's appearance, especially in the SI grades. But that's not always true. I was considering buying a second-hand 3-stone setting, set with two GIA Ex sidestones, both I color, VS2 clarity, from Blue Nile. One of the sidestones looked noticeably duller to me, especially when it was smudged with fingerprints. These stones were only about 1/3 carat each, but the cloud inclusion in one of the stones had a noticeable effect on the appearance of the stone. And these were VS2 stones!

And I agree, that when buying a stone sight unseen, just from the specs and the inclusion diagram, it's difficult to assess the impact of the inclusions on day-to-day performance just from the paper. We need to be more careful with our advice when consumers post that their newly purchased stone is not as "sparkly" as they thought. Typically, posters are told to clean the stone, etc. Better advice might include asking them about the nature and placement of inclusions, especially clouds.
 
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