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Thread: Nautilus pearl

  1. #751
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    Caption reads:
    microradiograph of a round 1.49ct Nautilus pearl revealing a centrally placed void or area of organic matter.
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  2. #752
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    Thanks, after contrast adjustment it is quite clear (the void, if not the coil shape).
    Steve
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  3. #753
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    I just bought Bari's book "Pearl". On page 21, it reads:

    "Mabe, a word of Tahitian origin, does not have any particular meaning, and we prefer to use the much more evocative term of blister pearl"

    I have read somewhere - I cannot remember where - that this word mabé designates the pteria species in a Japanese dialect from the Ryukyu islands. Can someone confirm or infirm?

    I did mention this to Hubert Bari when he sent me a draft copy of his first chapter back in 2008, I suppose he did his research but I'm still not convinced. None of my Tahitian contacts could confirm it is of Tahitian origin.
    Last edited by effisk; 02-15-2011 at 07:23 PM. Reason: typos

  4. #754
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    A new pearl received, obtained as others here from a private collection in a remote island location via 'friendly' persuasion. This is a 14-carat drop, and while it has notable blemishes and imperfections its general shape and wildly opalescent chatoyance make it unique for its size.

    Certainly these things are proving to be as consistent in type as their associated myth.
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    Steve
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  5. #755
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    Still from Tridacna? or else?
    CliClasp

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  6. #756
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    Quote Originally Posted by CLICLASP View Post
    Still from Tridacna? or else?
    M. Abominabilis ('the mystery mollusk'), due to its optical uniqueness and strange aragonite microstructure, a microstructure not as yet observed in any shelled mollusk of pearl-producing dimensions. That said, this is a very fine example of what has been revered for centuries in the Indo-Pacific as a Nautilus pearl.
    Steve
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  7. #757
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    That one is a beauty!
    GemGeek
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  8. #758
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    Quote Originally Posted by effisk View Post
    Caption reads:
    microradiograph of a round 1.49ct Nautilus pearl revealing a centrally placed void or area of organic matter.
    The microradiograph image from the privately-circulated, unpublished/unfinished Nautilus pearl monograph by Ken Scarratt of GIA Bangkok does raise eyebrows for the apparent shape of the irritant. The photo caption does not speculate an ID for this object and I do not know if the monograph attempts to draw any conclusions from it. Perhaps the image is offered prima facie for viewer's interpretation, given its provocative nature.

    As I mentioned prior to Effisk's posting of the image, the size of the object, at under 2mm (the X-Rayed pearl is approximately 5mm in total diameter) precludes its being a Nautilus embryo, as Nautilus develops during 12 months in a two-inch egg case and does not begin to resemble its species until somewhere near 15mm in size. Nautilus hatches fully-developed, with seven completed chambers.

    Subsequently I have been studying the extinct Ammonite class in order to compare it with modern Nautilus, and discovered that a major differentiating factor is that Ammonites cast thousands of eggs at once to the sea (vs. 9-12 per year for Nautilus), and the hatchlings, microscopic in size at around 1mm, boasted one functional chamber and a full whorl. Ammonite hatchlings were thus planktonic and spread throughout the pre-Tertiary seas, a factor in Ammonites' geographic ubiquitousness during hundreds of millions of years in the fossil record.

    The embryonic Ammonite hatchling is called an Ammonitella. If an Ammonitella were to be confirmed as the nucleous of a Nautilus (or any other) pearl, it's fair to say it would attract some serious attention from paleontologists, Ammonites having gone the way of the dinosaurs 65.5 million years ago.

    Today I began reading my newly-printed copy of Arthur Willey's Contribution to the Natural History of the Pearly Nautilus and almost immediately came across the following text. In 1894 Willey had just arrived in New Britain and began with a preliminary study of the area's plankton population as a means of beginning his search for Nautilus in its various stages of development (BOLD FACE IS MINE):

    Among many other objects, a small pelagic Mollusc known as Atlanta, belonging to the sub-order Heteropoda, was abundant at various depths. It was my first acquaintance with this small creature which is almost absurdly like a miniature Nautilus. It possesses in fact a perfect involute planorbiform shell, laterally compressed, symmetrical on both sides and not exceeding 5 millimetres in major diameter. Of course it differs essentially from Nautilus in that the cavity of the shell is not divided into chambers…

    The Atlantidae family is considered holoplanktonic, i.e. forming a part of the plankton population during its entire life.

    Clearly, this tiny 'Nautiloid' gastropod would provide an effective pearl-producing irritant regardless of the mollusk in which it happened to become trapped. Without having read the unpublished monograph, I can only hope and assume that the radiograph image in and of itself was not in any way used to defend the Nautilus-species certification.

    Below is the GIA radiograph (improved for contrast) and an image of a 1mm adult Atlantidae specimen. Its shape differs from the object in the pearl nucleus only in perspective.
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    Last edited by smetzler; 03-31-2011 at 01:16 AM. Reason: Replace illustration of Atlantidae for photograph, text to match.
    Steve
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  9. #759
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  10. #760
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  12. #762
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    Thanks for the new info. I have been starving for my nautilus update!

  13. #763
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    Ditto what Caitlin said!!
    Pattye


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  14. #764
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    A recently-acquired rare specimen of a Nautilus Pompilius Suluensis shell with albinistic tendencies. Notice the freshly-minted nacreous septum vs. the non-nacreous lining of the interior shell (covering its nacreous bulk).

    To further illustrate the aragonitic variety of Nautilus, and why one might even assume a Nautilus pearl to be non-nacreous.
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    Last edited by smetzler; 03-27-2011 at 05:49 AM.
    Steve
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  15. #765
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    That is fantastic!
    GemGeek
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