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Why your diamond goes dark or blue in direct sunlight

Discussion in 'RockyTalky' started by Garry H (Cut Nut), Dec 23, 2018.

  1. Wewechew
    Brilliant_Rock

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    by Wewechew » Jan 4, 2019
    Lol I guess we always want what we don't have- I have already been planning my next ring to be like yours.

    And oh my goodness, that five stone would be AMAZING!!!!!!
     
  2. sledge
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    by sledge » Jan 4, 2019
    Loving this thread. Haven't tried shooting pics of fiancee's ring since several months back. I'm getting motivated to try again.

    I don't have fancy cameras. Last time I tried, I had a tired iPhone 6+. This time around I have a few different choices:
    • Work phone = Galaxy S9
    • Personal phone = LG V40 ThinQ
    • Fiancee's phone = Galaxy S8
    Kudos to those making it look easy. I had a bear of a time trying to photo her diamond, which is why I haven't tried much since then, lol.
     
  3. the_mother_thing
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    by the_mother_thing » Jan 9, 2019
    So I finally managed to capture the two diamonds/rings I posted earlier in the thread in some sunlight. I wish I’d gone with a different cell phone cover/case, as this one really reflects (IMO) negatively in diamonds and almost makes it look gray/hazy, which it’s not. Nevertheless ... the soli has MBF, the 3-stone has no fluoro.

     
  4. FearlessSmile
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    by FearlessSmile » Apr 18, 2019
    I too received my partners ring an ACA form whiteflash and was worried when it went dark in the second video. However I’m guessing this is normal?



     
    


    


  5. OoohShiny
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    by OoohShiny » Apr 18, 2019
    The short answer is Yes.

    The longer answer is as Garry mentioned in the first post on this thread:

     
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  6. FearlessSmile
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    by FearlessSmile » Apr 18, 2019
    Thank you, also it’s only an iPhone 8 camera so probably not the best, plus the back of the phone is a dark grey colour.
     
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  7. FearlessSmile
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  8. John Pollard
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    by John Pollard » Apr 18, 2019
    @FearlessSmile that's great information on physiology.

    Here are some graphics showing how human eyes perceive "fire" - relative to the info above.
    https://www.pricescope.com/communit...parkle-more-in-dim-light.122718/#post-2144375

    And a supporting post from a prior thread.

    It's also worth remembering that the sun sub-tends light at about one-half a degree. This means that, in the entire 180-degree hemisphere, the sun is one tiny point light source occupying only 1/360 of the total area a diamond "looks" for light... So while you see the (very) bright sparkles that this single point source creates, the accommodation by our eyes (per the linked thread) makes the surrounding areas effectively dark.

    If you walked into a jewelry store and killed all of the lights in the ceiling except for one you'd get the same result, only the diamond would be even more dark since no jeweler's spotlight can rival our sun in intensity or ambiance...so powerful it makes Superman strong.

    Conversely, if we had 20 suns in the sky it would be like standing in the most amazing jeweler's showroom ever - but we probably wouldn't notice how groovy our diamond looked because we'd be hopping on the melted-slag of the sidewalks. :eek2:

    A good reminder for diamond-lovers when the sun comes out to play: One of the best viewing conditions for diamonds is under a leafy tree on a sunny day. The leaves above break the sun's single half-degree point source into many point sources, causing terrific brilliance as well as fire. Be careful though - you can stand there hypnotized by your finger-blinger for hours.

    Original post:
    https://www.pricescope.com/communit...l-cut-diamonds-revisited.150108/#post-2720418

    @Garry H (Cut Nut) Great that you bring fluorescence into the dialogue.

    Finally: A note about taking photos with phone cameras. Some have white balance settings you can manage. Others use AWB (auto). In most cases the default is set to incandescent/tungsten, which is great for indoor photos. But it will create blue in your outdoor shots.
     
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  9. FearlessSmile
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    by FearlessSmile » Apr 18, 2019
    Thanks for the explanation John :) I think I just freaked out when the diamond went dark even though the fire sparkle was crazy! (Also I was viewing it arms length so it would probably appear not as dark to someone standing further away observing?)

    My previous diamond I returned 58 table 34.5 crown 41.4 pavilion (triple gia excellent) didn’t seem to go dark like this, seemed bright white all the time, but it also didn’t sparkle that much until it was in the sun (not very good indoors/other lighting compared to my new one)
     
  10. EncikG
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    by EncikG » Apr 18, 2019
    @John Pollard slightly off tracked but it is my understanding that fluorescent only negatively impacts a small percentage of stones. If so, why does CBI not consider cutting stones with flouro?
     
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  11. Garry H (Cut Nut)
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    by Garry H (Cut Nut) » Apr 19, 2019
    The leafy tree effect is actually a little different. The light coming through the spaces in the leaves creates the effect of thousands of pin point lights and the result can be stunning!
    This is even more effective when the day is cloudy so that every bit of light is white (not blue on a sunny day).
    9.02.jpg
    And a photo captures only half of the fire and sparkle what we can see with 2 eyes!
     
  12. Dancing Fire
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    by Dancing Fire » Apr 19, 2019
    Garry, here are a few shots of my ring under the tree.
    IMG_0060.jpg IMG_0067.jpg IMG_0071.jpg
     
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  13. LightBright
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    by LightBright » Apr 19, 2019
    Gorgeous stone!! 55 table? I’d love to see angle details.
     
  14. John Pollard
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    by John Pollard » Apr 20, 2019
    Hi @EncikG - Thank you for asking. The problem actually isn’t chemical or mineral. It’s the absence of a crystal ball.
    :read:

    Here’s what I mean. We all know diamonds with fluorescence trade at lower values. We also know the level of devaluation loosely rises with the strength of the fluorescence. But the actual amount is inconsistent. Grading controversies and globalization haven’t helped this volatility. For right or for wrong, certain high-street traders and markets have decided to reject fluorescence entirely.

    Other diamond factories don't worry about this. They're cutting and selling in the moment, end of story. No returns. No backsies. Future volatility or devaluation will be someone else’s problem.

    We have always chosen to back our brand with long-term assurances to our retail partners. Doing this requires predicting long-term value for each diamond we craft. The value-volatility with which the industry treats high fluorescence makes those predictions impossible. This is why they're not included in our normal branded output.
     
    Last edited: Apr 20, 2019
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  15. Karl_K
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    by Karl_K » Apr 20, 2019
    Short answer its a market issue not a diamond issue.
    Long answer see above.
     
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  16. EncikG
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    by EncikG » Apr 20, 2019
    @Karl_K @John Pollard thanks for both the long and short answer

    I haven’t been in this forum that long but based on recent threads, fluorescent negatively affecting a stone might be over-hype and there seems to be a general liking to it here.

    On the issue of risk and volatility, these can often be mitigated by offering an alternate buyback or upgrade policy. Some might also view stones as a zero sum game already. Yet the fact is that the market trades it at a discount, what you view as a problem might actually be someone else’s solution as they chase a bigger caret and top cut.

    No doubt the PS community might only be a small percentage of the market, but market changes, not having a crystal ball myself perhaps blue might be the new black some day as I contemplate making pendent with a center blue (cut being priority of course)
     
  17. OoohShiny
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    by OoohShiny » Apr 20, 2019
    BGD are already covering off that eventuality, I would say ;-) lol

    CBI don't actively seek fluor but AGS Negligible does cover some stones with slight fluor - there was a thread quite recently on here IIRC, I think @Dancing Fire posted to say he'd love a CBI with fluor, but if you want one, it is the luck of the draw as to whether you get one, it seems! :D
     
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  18. EncikG
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    by EncikG » Apr 20, 2019
    @OoohShiny yup thanks, I think I read that thread. Great outcome.
    I had previously bought from BGD so was aware of their blue range. But it’s always nice to try another vendor :D
     
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  19. kmoro
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    by kmoro » Apr 20, 2019
    Sometimes the vendor screens separately to make sure the fluorescence really is “none” ... @John Pollard, does CBI do this or do they accept the lab grade of “negligible” where there’s a chance of fluorescence to just under medium ... is there a chance that any of the CBI diamonds do have some fluorescence?
     
  20. John Pollard
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    by John Pollard » Apr 21, 2019
    Sure. Our goal is identical brightness, fire and sparkle. We don't mind a little fluo as long as the crystal is perfect for our goal.

    It's always an interesting topic, lab grading. These are rocks. From the ground. A lot of “none” will fluoresce to some degree if you increase strength of UV or bring the diamond closer to the source. It's like "flawless" diamonds having inclusions when you zoom beyond 10X magnification. Nature made every diamond snowflake differently. The only part we can control is the crafting.
     
    Last edited: Apr 21, 2019
  21. Garry H (Cut Nut)
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    by Garry H (Cut Nut) » Apr 21, 2019
    Plus many of you have noticed a stronger fluoro reaction to the cheap UV pen lights. Taht is because the labs use the wrong too low frequency. Not the ones that really count. The ones that pass thru windows and give the beneficial effect of improving color.
     
  22. John Pollard
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    by John Pollard » Apr 21, 2019
    Just so, Garry.

    For anyone bored or just weirdly interested ;-) here's catch-up material.
    https://accreditedgemologists.org/lightingtaskforce/OvergradingColorMichaelCowing.pdf

    And this.
    https://www.pricescope.com/articles/blue-fluorescent-diamonds-color-grading-issues

    And if you have enough popcorn... 22 pages. Yes. You read that correctly.
    https://www.pricescope.com/communit...f-blue-fluorescent-diamonds-revisited.219341/
     
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  23. Wewechew
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    by Wewechew » Apr 22, 2019
    I’ve owned four CBI’s and only one showed any fluorescence.
     
  24. Texas Leaguer
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    by Texas Leaguer » Apr 22, 2019
    It's not well known because GIA does not emphasize the fact that "None" does not always mean none. One place that they do message it is on their report check site as you mouse over Fluorescence. GIA none disclaimer.png
     
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  25. Texas Leaguer
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    by Texas Leaguer » Apr 22, 2019
    As the number and variety of inexpensive UV emmiting devices have become commonplace, the AGS decision to depart from GIA reporting has proven itself to be a more rational and less confusing way to report on flurorescence. (The main confusion comes from the fact that the two labs report differently and the term 'negligible' is commonly ascribed an inaccurate definition). UV sources in the market stimulate WIDELY varying fluorescent observations.

    Fluoro was always considered by GIA to be an identification characteristic, not a performance characteristic. To whatever degree fluoro may possibly be a performance characteristic (color whitening or transparency degrading) it only achieves these effects in strengths of medium or stronger. Therefore, it can rightly be said that fluoro less than medium is of 'negligible' consequence.
     
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  26. Texas Leaguer
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    by Texas Leaguer » Apr 22, 2019
    Here's an image of a range of fluorescence in the Neglible range. You may not be able to make out the stone on the far left that is essentially inert. But note the GIA 'None' with very faint fluoro (second from right).
    fluoro compare negligible none.jpg
     
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