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  1. #1
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    Default Quality factors of pearls

    Hi,
    Is there anyone to explain me why the pearls have different lightning appearences, which define each grade of quality.
    What's going on the pearl's area to make these differences ?
    Thank's for your answers !
    Sincerely

  2. #2
    Pearl Enthusiast Senior Pearl-Guide.com Pearl Expert Pearl Dreams's Avatar
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    eric, you might want to take the PEARLSASONE course. You would learn all that and more:
    http://www.pearl-guide.com/forum/sho...ication-Course

    There is a code so you can take it free-- CPAAFREE.

  3. #3
    First-graft Pearl Senior Guide Member
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    Or go here: http://www.pearl-guide.com/forum/pea...p.php?tabid=64

    There is lots of free information about pearl grading for all the different types of pearls.

  4. #4

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    I would like to ask an additional question. Everyone sells "natural" Tahitians which now it seems come in all colors. What is the color of "natural" natural Tahitians? Can they be rainbow, pink, brown, or are these irradiated or colored pearls?

  5. #5
    Pearl Enthusiast Senior Pearl-Guide.com Pearl Expert Pearl Dreams's Avatar
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    nickie, the Tahitian pearls market is a cultured pearl market, not a natural pearls market. (Natural = wild, not farmed, not produced through human intervention.)

    The colors of cultured Tahitian pearls are natural, however (with the exception of so-called "chocolate Tahitians", which were popular a few years ago and are color treated.)

    Tahitians have body colors and overtone colors. The most common body colors are shades of gray or green. some are blue. Many pearls also have overtone colors that are most visible in diffuse lighting conditions.

  6. #6
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    Thank you Pearl Dream and cmd2014 !
    Infortunatly, PEARLSASONE seems not yet launched, even after accounting... It's a pity, because it will be perfect for me, in frensh...
    The topic about pearls given on this forum is very complete, but I have not found the reply to my question, which has been put in a wrong way.
    In fact, I should want to know what, materially, it's making different lightning on a pearl's area, more or less mirror.
    For exemple, I should be interested to find scientific studies about the physical phenomenon, in the framework of the nacre, doing that.

  7. #7
    Pearl Enthusiast Senior Pearl-Guide.com Pearl Expert Pearl Dreams's Avatar
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    PEARLSASONE was launched many months ago and many of us have completed the course! Edit: I see you meant the French version.

    http://www.pearlsasone.org

    I understand your question now. The arrangement of the aragonite crystals produces the luster. For articles check the GIA website (link to articles on pearls...many pages of articles: https://www.gia.edu/search/articles?q=pearls&start=0)

    and you may wish to read Pearls by Elizabeth Strack, also for sale by GIA.
    https://store.gia.edu/Pearls-by-Elis...-p/0201056.htm
    Last edited by Pearl Dreams; 08-02-2017 at 07:34 PM.

  8. #8
    Pearl Scholar Senior Pearl-Guide.com Pearl Expert pattye's Avatar
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    Nickie,

    Just a reminder that many pearl sellers, especially on ebay, call their cultured Chinese freshwater pearls Tahitian or Akoya to make them seem more valuable and come up in searches for Tahitian pearls or Akoya pearls. If you have questions about any particular online seller or their listing, feel free to link here and ask. There are a few trustworthy sellers on ebay.
    Pattye


    PatriciaSaabDesigns.etsy.com

    facebook.com/PatriciaSaabDesigns

    SO MANY PEARLS, SO LITTLE TIME----

  9. #9
    Rare Pearl Senior Pearl-Guide.com Pearl Expert JerseyPearl's Avatar
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    Yes, very good point pattye!
    Etsy shop: OceansCove
    Instagram: OceansCove
    Facebook: Ocean's Cove Jewelry
    Amazon Handmade: Ocean's Cove

  10. #10
    Rare Pearl Senior Pearl-Guide.com Pearl Expert
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    If you picture the surface of the pearl as being made up of little tiny transparent plates that all fit together. Layers of them going down to the centre. These little plates, The tighter they fit , the better they reflect the light. If the little platelets fit very tightly and are layered deeply then they better reflect the light and create lustre/shine. This is the simple explanation . This is why some pearls are shiny and some are more dull. It's a lot more complicated and I'm not going to go into Orient - you can read up on it in more detail on the links PD provided.
    Instagram Pearlzaustralia

  11. #11
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    Default

    Thanks for your all replies!
    I understand that so much these little plates fit tightly, so much the pearl reflect the light. But is the thickness of the conchyoline parralel to the plates, or between, which is most active ?
    I have readen that speed growth make little plate's sizes, giving a worse lustre to the pearl. So, maybe it's the percentage of conchyoline at a right angle to the layers which create variations of this effect ?
    I mean that the only first nacre layers work to give a perfect mirror effect, and then, the light don't go deeply in this kind of pearl.
    It's important for me to well know the inside of a pearl, before to cave it.

  12. #12
    Third-graft Pearl Senior Pearl-Guide.com Pearl Expert lilliefuzzysocks's Avatar
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    Default

    This book might help.
    Name:  AA.jpg
Views: 121
Size:  133.8 KB

  13. #13
    Third-graft Pearl Senior Pearl-Guide.com Pearl Expert lilliefuzzysocks's Avatar
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    Default

    I believe the course in French almost ready or finished...

  14. #14
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    Default

    When I have wanted to acceed to the course, 599 dollars were required ?!
    Sure it's a nice book, just seeing cover, but with my very poor english, I'll need two months to understand it... As usual, there's almost not any books in frensh.
    I have readen something about "maeshori", treatement which can upgrade dull pearls, but how many grades is possible to win, one or two A, or more ?
    Reading that, the lustre seems really just an area's effect, so I can't provide what quality of nacre I'll find carving the pearl.
    Do you know if there are big differences between area and deeper layers ?
    Last edited by ericw; 08-04-2017 at 09:21 AM.

  15. #15
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    Hi Pattye,
    Thanks for your prevention ! One of my greatest concern is to know what kinds of nucleus, and there sizes, inside any pearls.
    Even "keshi" pearls are often sold with a hard nucleus by chinese sellers, as I have received that.

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