Strong blue fluorescent

[waterlily24]

Hi,

Anyone has any idea how many percent of stones have "Strong blue fluorescent" will appear hazy and cloudy?
Why only some of them will be hazy? I thought the fluorescent should not affect the normal light return.
How much the characteristic will affect the value of the stone?

Thanks.

 

[Lorelei]

Date: 10/31/2009 9:47:19 AM
Author:waterlily24
Hi,

Anyone has any idea how many percent of stones have 'Strong blue fluorescent' will appear hazy and cloudy?
Why only some of them will be hazy? I thought the fluorescent should not affect the normal light return.
How much the characteristic will affect the value of the stone?

Thanks.

Ok to put this into perspective, one of our experts has been involved with diamonds for many years. Out of the strongly or very strongly fluorescent stones he has inspected, he said he can count on the fingers of one hand how many have been ' overblue' or shown negative effects from it. Colourless diamonds are normally discounted for fluorescence but apart from that it depends.

 

[brandithib]

I find diamonds with a strong blue fluorescence have a "purplish" glow to them, not necessarily oily or hazy. It''s not my personal preference but many seem to love it. I was considering a fluorescent stone but changed my mind when I saw one in person next to a non-fluorescent. I saved a photo I found on PS that sort of give some perspective. It''s not my photo and I forgot who it''s for. I hope I''m not breaking any rules by re-posting it. The princess stone has no fluorescence but the round has strong ( I believe )

 

[FB.]

Yes, Lorelei is right; not many strong or very strong fluor stones have serious optical issues.

I'm a bit "into" fluor stones and I'd suggest that a slightly higher risk for haziness or opaque, or otherwise nasty appearance, is increased with the following features in the stone:

SI2 clarity or lower.
Large numbers of clouds - especially if: "clarity grade is based on clouds....".
Significant amounts of twinning wisps.
Significant amounts of graining.

(all of the above might make an SI2 one of the actively-sought-after "eye clean" stones, as compared to crystal inclusions that seem less likely to be eye clean in SI2 or lower grades but also may be less likey to cause milkiness)

But that's not to say that stones with the above inclusions will be troublesome (or that a flawless stone will not be troublesome) - only that I have a suspicion that the above have a higher risk.

The best thing is to ask the seller and/or take advantage of their returns policy.

 

[FB.]

Date: 10/31/2009 10:45:28 AM
Author: brandithib
I find diamonds with a strong blue fluorescence have a 'purplish' glow to them, not necessarily oily or hazy. It's not my personal preference but many seem to love it. I was considering a fluorescent stone but changed my mind when I saw one in person next to a non-fluorescent. I saved a photo I found on PS that sort of give some perspective. It's not my photo and I forgot who it's for. I hope I'm not breaking any rules by re-posting it. The princess stone has no fluorescence but the round has strong ( I believe )

The pic you've shown has the look of a fluor stone that has been illuminated with a UV torch.

The more normal look of a very strongly fluorescent stone in direct sunlight is like this:
(it's a GIA-cert, 1.1ct, D, VS1, pear, VSB fluor, cut to very good proportions)

 

[AshNZ]

The research indicates 1% of stones have the ''OverBlue'' effect. Fluorescent stones make up 33% of all of the stones to go through GIA. So 1% of 33% is not a lot...
This is no association with strength of fluorescene and likelihood of getting an Overblue.

Fluorescence IMPROVES light return through the conversion of UV light to visible light. The distate for fluorescence is not based on science or beauty, just fear in the 1970''s which has not been corrected to this day.

Fluorescence does alter the color of a stone in UV light - this is important as this is a personal choice.

 

[kenny]

Date: 11/1/2009 9:07:24 PM
Author: AshNZ
The research indicates 1% of stones have the 'OverBlue' effect.
Fluorescent stones make up 33% of all of the stones to go through GIA.
So 1% of 33% is not a lot...

Just a little nit pic with the math.

"1% of 33%" would be 0.33% of the total, which is not the case.

If:
1. One percent of ALL stones are "overblues"
2. All "overblues" are (a subset of) fluorescent
3. 33% of GIA stones have fluorescence

then

3.3% (not 0.33%) of GIA fluorescent stones are overblue.

Ithink I have this right.

 

[AshNZ]

Date: 11/1/2009 9:23:35 PM
Author: kenny

Date: 11/1/2009 9:07:24 PM
Author: AshNZ
The research indicates 1% of stones have the ''OverBlue'' effect.
Fluorescent stones make up 33% of all of the stones to go through GIA.
So 1% of 33% is not a lot...

Just a little nit pic with the math.

''1% of 33%'' would be 0.33% of the total, which is not the case.

If:
1. One percent of ALL stones are ''overblues''
2. All ''overblues'' are (a subset of) fluorescent
3. 33% of GIA stones have fluorescence

then

3.3% (not 0.33%) of GIA fluorescent stones are overblue.

Ithink I have this right.

0.33% of all stones through GIA are OverBlue

I should have said 1% of all Fluorescent stones...

 

[yssie]

Date: 10/31/2009 10:45:28 AM
Author: brandithib
I find diamonds with a strong blue fluorescence have a ''purplish'' glow to them, not necessarily oily or hazy. It''s not my personal preference but many seem to love it. I was considering a fluorescent stone but changed my mind when I saw one in person next to a non-fluorescent. I saved a photo I found on PS that sort of give some perspective. It''s not my photo and I forgot who it''s for. I hope I''m not breaking any rules by re-posting it. The princess stone has no fluorescence but the round has strong ( I believe )

This is a really interesting comparison photo, thank you for posting it!

 

[kenny]

Thanks Ash.

 

[FB.]

Overblues are rare, so I doubt that we could accurately quantify their numbers - so I wouldn''t get too caught-up in trying to give a percentage.

Sometimes the sheer strength of the fluor in VSB stones makes you think that the stone is hazy because it has a blue colour to it and because it is emitting the blue light in all directions. But if you examine the stone, your ability to see inside the stone is not affected.
Ask the seller how it performs and make sure that you have a good return policy if you have any doubts.