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Why your diamond goes dark or blue in direct sunlight

Garry H (Cut Nut)

Super_Ideal_Rock
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There has been another discussion about this topic, and the idea that Fluorescence plays a part. So I did a small test today with various different cuts.


Shaded daylight at 11am, close to the solstice, in Melbourne taken just now on 24th December. The shade is from my body. My hand was vertical and you can see me in the wedding ring and the blue cloudless sky. Its a hot day +30C 90F.

Note in direct sunlight the ideal-cut round diamond is showing blue from the sky and dark because the light from the sun is only lighting up a few facets. The sun is a very small point light source.
The other fancy shapes all have crushed ice effects because there are many small virtual facets and those stones are glowing with various reflected light bouncing all around in the stones.

The strongest fluorescence is in one of the cushions and the marquise. Fluoro has nothing to do with how the diamonds appear in daylight (other than improving their colour). In some very strong diamonds there may be a blueish sheen that gives some a fright or make others happy.

So looking at a really top cut diamond in direct sunlight is not a judge of anything.
 

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kmoro

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There has been another discussion about this topic, and the idea that Fluorescence plays a part. So I did a small test today with various different cuts.


Shaded daylight at 11am, close to the solstice, in Melbourne taken just now on 24th December. The shade is from my body. My hand was vertical and you can see me in the wedding ring and the blue cloudless sky. Its a hot day +30C 90F.

Note in direct sunlight the ideal-cut round diamond is showing blue from the sky and dark because the light from the sun is only lighting up a few facets. The sun is a very small point light source.
The other fancy shapes all have crushed ice effects because there are many small virtual facets and those stones are glowing with various reflected light bouncing all around in the stones.

The strongest fluorescence is in one of the cushions and the marquise. Fluoro has nothing to do with how the diamonds appear in daylight (other than improving their colour). In some very strong diamonds there may be a blueish sheen that gives some a fright or make others happy.

So looking at a really top cut diamond in direct sunlight is not a judge of anything.
Thank you for this! I feel like it was made for me.

I still don’t like the look of a stone while it is fluorescing ... and if I have a stone that does, I would prefer to have a suitable discount in my pocket.
 

sledge

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Thank you for this! I feel like it was made for me.

I still don’t like the look of a stone while it is fluorescing ... and if I have a stone that does, I would prefer to have a suitable discount in my pocket.
In the first pic, Garry is saying the blue you see is not because fluor but because of the blue sky reflecting and him creating a shadow (on purpose) to starve the diamond of light to reflect back thereby making the stones also appear dark.

Additionally the cushion and marquis shapes have a crushed ice effect and are reflecting light differently than the round ideal who doesn't have that effect. @Garry H (Cut Nut) I am curious what are the LGF's on the round? I know many prefer 75 for fatter arrows and biggger bolder flashes. Also 75 tends to do better in indirect or softer lighting. 80+ LGF tend to do better in bright lighting but can also have a splintery flash and skinny arrows. Seeing an ideal round with varying LGF values in this picture would add a little further interest for the shadow pic.

My fiancee's stone is a BGD Blue H VS2 with MBF. We've been in a variety of lighting conditions and don't get a blue sheen or negative effect from the fluor. Granted the part of night clubs and black lights is not a concern. I did get a UV light with my stone and it does glow similar to the 2nd pic Garry showed.

I would agree that if getting a stone with medium+ levels of fluor then you need to ensure you are getting a discounted price as those stones do trade for less. IMO the discount is based more on prefence and desirability, or in this case lack thereof, versus a true performance metric.
 

kmoro

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In the first pic, Garry is saying the blue you see is not because fluor but because of the blue sky reflecting and him creating a shadow (on purpose) to starve the diamond of light to reflect back thereby making the stones also appear dark.

Additionally the cushion and marquis shapes have a crushed ice effect and are reflecting light differently than the round ideal who doesn't have that effect. @Garry H (Cut Nut) I am curious what are the LGF's on the round? I know many prefer 75 for fatter arrows and biggger bolder flashes. Also 75 tends to do better in indirect or softer lighting. 80+ LGF tend to do better in bright lighting but can also have a splintery flash and skinny arrows. Seeing an ideal round with varying LGF values in this picture would add a little further interest for the shadow pic.

My fiancee's stone is a BGD Blue H VS2 with MBF. We've been in a variety of lighting conditions and don't get a blue sheen or negative effect from the fluor. Granted the part of night clubs and black lights is not a concern. I did get a UV light with my stone and it does glow similar to the 2nd pic Garry showed.

I would agree that if getting a stone with medium+ levels of fluor then you need to ensure you are getting a discounted price as those stones do trade for less. IMO the discount is based more on prefence and desirability, or in this case lack thereof, versus a true performance metric.
Hi @sledge ! thanks as always another thoughtful reply.

To be clear, I do understand that Garry was talking about the sky reflection ... which I think is actually really cool, lol.

I have been reading carefully. I think I get it. And you're right, I can't see anything other than beauty in the sunlight - I love the way the blue that I see is the sky reflection. I was only questioning the blue as I did not know it was the sky and had just discovered the blue flourescence.

Also, I am not trying to put down diamonds with fluorescence. I understand that it only affects clarity maybe 1% of the time. And I think it is a great deal to find a fluorescent diamond for a bit less $ than those without. I know you have the gorgeous BGB and don't mind the fluorescence.

However, I do find the fluorescence just too close to medium, in my case, for my taste. I do find myself in situations with black light; also, now that I've seen it, it is a mind-clean issue. And a wallet issue, haha - because I could go for BGB.

When comparing to the pics, I am really only comparing to the bright glow, not the crushed ice appearance, although when my diamond glows, it does appear a bit hazy - I can't see the facets the way I can with my GIA none. To answer your question, the LGF's are 77. But ... still ... it's only the neon light thing that I don't like. If it was closer to to the other end, like Garry's stone on the right, I would consider keeping it ... but still, I don't like that much flouro either, even if it is well within AGS negligible.

So - in the end, when I do the upgrade, I will make sure someone has a look at it to see if it is closer to my preference.

As so often mentioned, this is just about personal preference. This has nothing to do with light performance (breathtaking, btw).

My vendor is already bending over backwards to help me out with a situation that is entirely my fault, nothing to do with light performance, and purely my preference. How is that for service??!!!

Thank you to all of you that have taken the time to help me understand! You are all awesome!

Merry Christmas & Happy Holidays!

:wavey:
 

Matthews1127

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@Matthews1127 in the last pic you would have got a very awesome show as you rotated your hand and the large virtual facets came to life and danced in the center.(3 bright bars in the photo).
I’ll have to take a video, next time!! It’s so difficult to capture the true, light show performance of diamonds in photos & video. I did see the dancing bars, IRL, but the photo only captured a sliver of that!!!
 

Garry H (Cut Nut)

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GIA rounding means the lower girdle info is useless. I think it would be mid way between 75% and 80%.
Yes, Matthews, videos would show better what you are demonstrating. But what 2 eyes see is far better than a single lens.
Anyone else want to show their goodies in various light?
 

sledge

Ideal_Rock
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GIA rounding means the lower girdle info is useless. I think it would be mid way between 75% and 80%.
For those reading along and not in the know...
  • GIA reported 75% value = 73-77% actual value
  • GIA reported 80% value = 78-82% actual value
 

marcy

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Great thread. This is how I found PS. My first AGS0 went dark in sunlight and I was sure there was something wrong with my diamond.
 

Johnbt

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Three pics, all taken within a few minutes on the Outer Banks of North Carolina. That's the color they call Carolina blue - at least if you're a fan of the University of North Carolina. We're from Virginia.

It's a WF ACA 1.514 F VVS2 set in platinum. These were taken later in the afternoon, as you can tell from the angle of the shadow.
I tried a number of times to get a clear shot with the sun shining directly on the top of the stone, but the iPhone 6s couldn't handle the bright reflections.

5A234267-2636-4683-A01E-3FB44C3DC20E.jpeg D7267BED-8062-4938-994A-4B855B60C690.jpeg beach 5.jpg

Otherwise it's just been a plain old beautiful dazzling diamond. :sun:
 

KristinTech

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0.90 F SI1 CBI from HPD (Stuller 10k rose gold)


Near a large window:
2EB28D52-43AB-46E2-9957-FA26CB7FA3EC.jpeg

Thinking I broke it—sitting in a theater awaiting a performance. House lights were still up. Many spotlights above me.
7F67E578-EA0F-48D9-A98A-AE81FD9B20C1.jpeg


Playing with sun and shade here.
124F83AE-758B-4F3F-9465-772BE99932D9.jpeg B7B89D7D-4E8B-425A-8951-B15E84A47832.jpeg


At the threshold of sun/shade in the afternoon sun:

9DA1B9AA-E02A-4AB3-B20D-34E136830E2F.jpeg


Dang it, I broke it again! With my F oval:

EDC06C12-CA5D-4568-A8A5-DED022CCEDDA.jpeg


Phew—fixed it!!!

31E2F758-C9D4-4B7E-8799-9B27F441B6E7.jpeg


Next up, a series of pics— this is a good representation of what my eyes see on my couch during daylight (window at back). A pinwheel rainbow effect.
A19BFD63-A7D3-4B14-82CE-57DA7FCFC702.jpeg

Zooming in with the camera.
C93E31B6-B998-4AF9-9E3F-5B1A3E59466C.jpeg


Zooming in further, you can see my blinds. My profile picture is zoomed even more!
613914ED-E4AD-4178-9A36-666DBED1E2F0.jpeg
 

the_mother_thing

Ideal_Rock
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AWESOME & educational thread, Gary; thank you! :clap:

Here are a couple of mine I just took. The soli diamond is AGS000 with med blue fluoro. The others are also ACA/ideal cuts. Note it’s a cloudy/overcast/rainy day here today (mid-Atlantic U.S.). Pics taken with iPhone XR. My cell phone is white with a clear, glittery cover that may impact the diamonds’ appearance somewhat (with my old phone/cover, I saw more contrast/black reflecting from that phone’s cover when taking pics of diamonds). Now, I usually see the arrows appearing gray/white with this one.
F2D12201-5425-4493-A9B5-AF16EB52815F.jpeg

Outdoors with diamonds facing me/camera & the sky. Here, I’m not sure if fluoro is at work or if it’s my cell phone’s cover reflecting in the soli, or if it’s a combination of that with the difference in setting style (more open soli vs. bezels in 3 stone) ... I welcome thoughts/opinions:
FB37C8B3-7594-4535-9A42-9AD7D6205842.jpeg

Outdoors, in natural overcast light:
BBA58255-E5E7-4B4F-BF7F-7831D952373E.jpeg

Outdoors, with flash:
D2F177B0-F5D0-4846-9120-B3C7DC51FB9D.jpeg

Indoors, with black light:
C1BB1446-D9EB-4202-A5B1-D8FE136392C0.jpeg
 

the_mother_thing

Ideal_Rock
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I just gave my soli a quick cleaning from the previous pics, and took both rings out back, and had them facing the cloudy, overcast sky. The soli diamond seems to reflect it more than the bezeled diamonds; it’s not ‘cloudy’ itself. Is the reflection aspect because it’s bigger than the others, or because the setting is more open/lets more light into the diamond vs the bezeled diamonds, or is that a reaction due to the fluoro?

Do bezels generally just make diamonds appear more ‘contrasty’? Maybe that should be a separate thread topic. :think:

350CD8B3-6C40-4864-AA21-D3DA32F0493E.jpeg
 

Garry H (Cut Nut)

Super_Ideal_Rock
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Three pics, all taken within a few minutes on the Outer Banks of North Carolina. That's the color they call Carolina blue - at least if you're a fan of the University of North Carolina. We're from Virginia.

It's a WF ACA 1.514 F VVS2 set in platinum. These were taken later in the afternoon, as you can tell from the angle of the shadow.
I tried a number of times to get a clear shot with the sun shining directly on the top of the stone, but the iPhone 6s couldn't handle the bright reflections.

5A234267-2636-4683-A01E-3FB44C3DC20E.jpeg D7267BED-8062-4938-994A-4B855B60C690.jpeg beach 5.jpg

Otherwise it's just been a plain old beautiful dazzling diamond. :sun:
We need the photo in the shade of your body too please
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,581
I just gave my soli a quick cleaning from the previous pics, and took both rings out back, and had them facing the cloudy, overcast sky. The soli diamond seems to reflect it more than the bezeled diamonds; it’s not ‘cloudy’ itself. Is the reflection aspect because it’s bigger than the others, or because the setting is more open/lets more light into the diamond vs the bezeled diamonds, or is that a reaction due to the fluoro?

Do bezels generally just make diamonds appear more ‘contrasty’? Maybe that should be a separate thread topic. :think:

350CD8B3-6C40-4864-AA21-D3DA32F0493E.jpeg
Not sure, is the Soli a lower color?
in the cloudy light laying down the soli appears very clear - there would be enough UV in tat situation to induce haziness if it were present.
 

Johnbt

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"We need the photo in the shade of your body too please"

I know, but it keeps raining in Virginia. Day after day and always when she has a day off. I don't know if I can take another year of rain. The photo may have to wait until our next trip to North Carolina; unless I can get her to join me in retirement soon.
_____________

I bought a $9 LED UV Craftsman flashlight at Lowe's today. I think it needs a dark filter because everything turns blue when it's on. There's enough light to read a book at arm's length in a pitch black room. I'll keep trying.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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"We need the photo in the shade of your body too please"

I know, but it keeps raining in Virginia. Day after day and always when she has a day off. I don't know if I can take another year of rain. The photo may have to wait until our next trip to North Carolina; unless I can get her to join me in retirement soon. Feeling Blue
_____________

I bought a $9 LED UV Craftsman flashlight at Lowe's today. I think it needs a dark filter because everything turns blue when it's on. There's enough light to read a book at arm's length in a pitch black room. I'll keep trying. You need to put the rings in the dark. Under a desk etc. The UV light may not need to be directly from the front. If need be make a pin hole cover.
 

the_mother_thing

Ideal_Rock
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Not sure, is the Soli a lower color?
in the cloudy light laying down the soli appears very clear - there would be enough UV in tat situation to induce haziness if it were present.
The soli diamond is an AGS K, and the 3 stone diamonds are also AGS/GIA J/K diamonds (no fluoro), so I have to think it’s either: 1) the fluoro; or, 2) the open vs. bezel setting.

If we get a sunny day sometime this week (raining again today), I’ll take more pics outside of the two rings. :wavey:
 

Wewechew

Brilliant_Rock
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I just gave my soli a quick cleaning from the previous pics, and took both rings out back, and had them facing the cloudy, overcast sky. The soli diamond seems to reflect it more than the bezeled diamonds; it’s not ‘cloudy’ itself. Is the reflection aspect because it’s bigger than the others, or because the setting is more open/lets more light into the diamond vs the bezeled diamonds, or is that a reaction due to the fluoro?

Do bezels generally just make diamonds appear more ‘contrasty’? Maybe that should be a separate thread topic. :think:

350CD8B3-6C40-4864-AA21-D3DA32F0493E.jpeg
My bezels seem to darken my ideal cut diamonds. I didn't see the modification you did to your Sholdt until after I received mine. I think how you did yours is the way to go to maximize light play in the stone.
 

Johnbt

Shiny_Rock
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"The UV light may not need to be directly from the front. If need be make a pin hole cover."

Thank you for the suggestions. I will certainly try them.

Meanwhile, it's raining again and the sky is a beautiful uniform gray. It's 1 p.m. and no sun, no shadows.
 

the_mother_thing

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My bezels seem to darken my ideal cut diamonds. I didn't see the modification you did to your Sholdt until after I received mine. I think how you did yours is the way to go to maximize light play in the stone.
Thank you, though I’m kind of torn because I really like how contrasty the diamonds in my three-stone look when they move around whereas the soli diamond is just all brightness/white. (I emphasize ‘just’ because I think that’s what most people want to see - a bright diamond; but I’m an oddball that wants more contrast with the arrows & facets). It kinda makes me wonder if I shouldn’t have at least semi-bezeled it (vs the 4 tab/prongs). I love bezels/semi-bezels, but I think I’ll try to get a little more mileage out of this setting before I do anything drastic, as I’ve only had it for about 6 months now. And by drastic, I mean maybe see about finding a match for the center diamond of the 3-stone, and using all the diamonds to make a 5-stone. :shifty:
 
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