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Triassic Nautiloid Pearl Blister

SteveM

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DWhatley;178505 said:
Now that you have freed that piece of memory for other knowledge, how do they seed cultured pearls?
Welcome the opportunity to free another neural region of a little detritus.

The process stolen and thereafter perfected/patented by Koichi Mikimoto in the early 20th century involves surgical creation of a pearl sac by inserting a small piece of mantle tissue into the flesh of the animal (grafting), thus assuring that a cyst is formed of mantle epithelial cells producing the same aragonite microstructure as the inner lining of the shell (most commercially: nacre/mother of pearl). The primary objective is round shape, so uncommonly found in nature. To guide the shape and guarantee pearl size, a round shell bead is introduced at the same time as the mantle tissue. The bead is then coated with the shell material, resulting in an inverted shell (exterior within, interior without). Eventually it was discovered that insertion into the oyster's gonad would doubly assure that the sac would become round, the gonad also serving as a less surgically-sensitive organ.

The success of this model literally destroyed the natural pearl business by the mid-20th century (not to ignore overfishing by a new generation of pearl divers with air supply), as women could obtain perfectly round and shiny 'pearls' at a tiny fraction of the price Indian Rajahs and robber-baron matrons traditionally paid for the real thing. But in the end, such 'pearls' are nothing more nor less than nacre-coated beads in the eyes of the purist.

Mantle tissue without the guiding bead is also done, typically resulting in baroque pearls known as keshi, although the Chinese freshwater mussel pearl industry has perfected its grafting technique to the point that the bead is no longer necessary to obtain symmetrical shape.
 

DWhatley

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This is a very dangereous topic :biggrin2:. I have the feeling that "real" pearls, from whatever animal makes them are not in my hobby budget and I am not likely to find any on my own but more reading is tempting. Is there a visual (ie with only the eye) way to distinguish cultured pearls (I assume the term is still correct?) and natural ones? Using commonly available (more or less) tools, would weight per diameter be an indicator since the inside of a cultured pearl does not contain the same material?

Lastly, to ensure we stay on topic, what cephalopods (as I mentioned I saw the one octopus pearl) produce pearls today and which are suspected of producing them in the past. Of the ones found today, is there an area of the world where they are most common?
 

SteveM

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DWhatley;178551 said:
This is a very dangereous topic :biggrin2:. I have the feeling that "real" pearls, from whatever animal makes them are not in my hobby budget and I am not likely to find any on my own but more reading is tempting. Is there a visual (ie with only the eye) way to distinguish cultured pearls (I assume the term is still correct?) and natural ones? Using commonly available (more or less) tools, would weight per diameter be an indicator since the inside of a cultured pearl does not contain the same material?

Lastly, to ensure we stay on topic, what cephalopods (as I mentioned I saw the one octopus pearl) produce pearls today and which are suspected of producing them in the past. Of the ones found today, is there an area of the world where they are most common?
First of all, 'pearls' (read: 'concretions') are innate to all organisms as anomalies. On topic, true pearls are calcium carbonate biomineralizations from shelled mollusks. Dave LeBlanc's octopus pearl is certainly an anomaly, but holds some intrigue for the concept of latent ectocochleate genomics of Cephalopoda.

The only Cephalopod pearl in the literature is Nautilus (albeit unsubstantiated scientifically—my current challenge), and of course the geographical restrictions would match Nautilus/Allonautilus habitat. Regions with particularly strong cultural/mythical regard for Nautilus pearls are the Sulu Archipelago in the Philippines and nearly all of Indonesia. Then there is the one Arthur Willey claimed to have found in 1896, in the Bismark Archipelago.

By international agreement, 'pearl' is a word that may only be used commercially for natural, or wild, pearls. Cultured pearls sold without the qualifier are not legal tender, under FTC restrictions. For telling natural pearls from cultured without technology, nearly impossible without experience (thus the commercial success of pearl culturing). The bead used in culturing is mussel shell nacre with the same density. Gemological laboratories with great depth of experience and a battery of sophisticated equipment certify natural pearls for the collector and investment community, and as you might imagine there are shady types that go to any lengths to confuse them—requiring ever greater technology. Very much akin to the tit-for-tat that goes on in the computer virus world.
 

DWhatley

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It would seem that someone would have "seeded" a nautilus to see if it produced a pearl. The thought assumes the process would be similar to seeding mollasks. The animal would have to live long enough to allow growth (a challenge in an aquarium) and seeding could only validate (but not invalidate) the potential but it seems like an obvious experiment.
 

SteveM

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DWhatley;178568 said:
It would seem that someone would have "seeded" a nautilus to see if it produced a pearl. The thought assumes the process would be similar to seeding mollasks. The animal would have to live long enough to allow growth (a challenge in an aquarium) and seeding could only validate (but not invalidate) the potential but it seems like an obvious experiment.
The results of culturing a Nautilus blister are highly predictable, and are already known from the natural blisters found in anomalous shells and fossils. This does not help us to explain the highly unusual composition of putative Nautilus loose (whole) pearls, which appears to have something to do with the unique and periodic biomineralization process of the inaccessible rear (septal) mantle. The hope at some point is that there will be enough phylogenic-related scientific curiosity to pursue this aside from commercial considerations. Besides, can you imagine the physical plant required to farm 100s if not 1000s of Nautiluses to make a go of pearl production on a commercial scale…
 

DWhatley

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Sorry for my lack of background. Is it both the free form (not blistered) and material being non-nacre that is the curiosity and linkage or just the non-nacre substance?
 

SteveM

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DWhatley;178570 said:
Sorry for my lack of background.
D.,

Join the club. It's only been a few days since I brought this to the attention of TONMO, so it is only natural that folks here would desire a ready resolution. We've been at it for nearly four years now.

All that is known is that the pearls in question are indeed non-nacreous natural aragonite pearls from a saltwater mollusk, claimed by Indo-Pacific pearl traders as Nautilus with no reasonable alternative. They are certainly rare, and certainly fascinating (my avatar). It was just one year ago at the University of Granada that their Paleozoic (and modern Monoplacophoran) aragonite microstructure was observed, since reconfirmed by state-of-the-art crystallographic analysis. This has brought some pretty significant scientific minds to bear, but the serious work is just getting started.

I refer to the mystery mollusk—until such time as pearl linkage should somehow be confirmed—by the tongue-in-cheek taxon 'Molluscus Abominabilis' (M. Abominabilis). Nautilus or 'Naut', these pearls offer some pretty amazing theoretical challenges. And they have opened my completely untrained eyes to the world of Cephalopoda, Paleontology and TONMO!

P.S.: If these pearls are indeed Nautilus, this will only be determined via a thorough, even unprecedented, investigation of Nautilus biology. The pearl experts are of very little use at this point…
 

Pr0teusUnbound

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interesting!
ive heard of similar formations in fossil goniatite and ammonite shells. the pearls were usually smaller, more flush with the shell surface and found on the lateral and ventral lining of the body chamber.
 

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