Nautilus pearl

If it is a pearl, and not carved out of shell, it is much more likely to have come from Tridacna gigas, but this is highly unlikely. Anything of size is usually attached to the shell and not round. Honestly, what you are showing looks like it was carved from shell. Try shining a single spotlight above it to look for a "ring of fire" flame pattern that might indicate that it is a pearl.

The first photo in your post looks like an operculum and not a pearl at all. Can you tell me what the post number was?

I recall the discussion. Everyone agreed the specimen was gastropod operculum.

As for the other images, Blaire is correct that it's carved shell. All pearls present with closed, fully enveloped concentric lines radiating outward from the nucleus, but this piece has visibly bisected lines, meaning it was cut from a large, thick shell. The color and structure is consistent with Tridacna gigas.
Thank you for the comment.
The post #579
I thought so also when first saw the pearl, that is was carved from a thick shell.
But one day I got pictures of beads that made from shell, I noticed a few differences. First the carved one looks like marble on the surface and more than half of this pearl covered by wax like layer or plastic and 1/3 of the pearl surface (part) has light brown colour. I also noticed that the carved one has irregular form of circle. naut1.jpgnaut2.jpg naut3.jpgnaut4.jpgnaut5.jpg

There are at least six visible layers. The lower four, prismatic and the upper two aragonitic. (calcareous --> nacreous). The profile of those outer layers are typical of the cloudy, snow-globe appearance of Tridacna gigas shell and pearls. It that were a pearl, they'd be spread out uniformly across the entire surface, instead at one end as this image shows. The straightness of the lines (growth fronts) and the distance between also support originating from a very thick shell.

Likewise, many times Tridacna pearls found in blister form are cut away from the shell, ground to shape then polished, but this piece has no evidence of that either.

Clearly, cut shell.
Thanks, Was it lab tested? the swirling pattern could also look like carved out from the shell, sorry
Thank you for the comments.
I am planning to have lab test in a few days.
I attached photos of beads and carving made from Tridacna Shell for comparison.
Beads made from shell will show the swirling pattern clearly on the surface and also has irregular pattern. The swirling pattern on this pearl (hopefully) is not clearly visible without flash light. Also the swirling pattern is too perfect get from a shell and the pattern is the same as the shape of the pearl. Any comment is really appreciated.
The past owner said his father found the pearl on the beach around 45 years ago, he was little at that time.IMG_1725.JPGIMG_1726.JPGIMG_1727.JPGIMG_1728.JPG
I still think it is too big to be true. The choice is whether it is a real pearl or carved from shell but comparing it with the shell beads also looks different. Its shape is oval, not round and bottom part has slightly darker than top part. I hope more pictures will help. Thanks.IMG_6564.jpgIMG_6824.jpgIMG_6580.jpgIMG_6833.jpg
Not a pearl. Remember that pearl and the material that lines the inside of the shell both contain aragonite. And notice that it says polished. Thank you for sharing your report.
If there is any flame structure present, one of your images appears to show some very weak flames where the light is reflecting off the surface, then it is either Tridacna shell or a fashioned (worked and polished) Tridacna pearl. I have seen Tridacna pearls with BANDING, including whole pearls, blisters and blister pearls, so ID is not always straightforward and can be very subjective. Good luck getting everyone to agree on this piece!
Thanks for the answer. I am really new to pearl. Maybe it is a kind of coconut pearl.
How about this orange pearl/stone ? lab2.jpgIMG_1806.jpgIMG_1808.jpg
Very interesting piece. Looks like Adamas need an X-ray machine to help out, not that Tridacna pearls usually show much via X-rays. If it is another type of pearl X-rays may well help!
If there is any flame structure present, one of your images appears to show some very weak flames where the light is reflecting off the surface, then it is either Tridacna shell or a fashioned (worked and polished) Tridacna pearl. I have seen Tridacna pearls with BANDING, including whole pearls, blisters and blister pearls, so ID is not always straightforward and can be very subjective. Good luck getting everyone to agree on this piece!

I missed this. Thanks for the information on the banding. :)
For those of you following the exchange with "Whatever", I have deleted the posts. I did this because things had gotten out of hand and also because "Whatever" did not listen to the instruction to start another thread.
Unfortunately, the page link above isn't working for me. I was able to find it with Google:

It's outstanding so far. I can see that it will take some time to fully appreciate it. :)

It's fixed now. Thanks for pointing that out.

And yes, outstanding indeed.
The putative Nautilus pearls in this thread could never become ammolite, which is petrified nacre. That said, just think if a nacreous pearl could be transformed as was this hefty chunk of ammonite aperture!

A rare specimen, 100% gemstone:

View attachment 26498

Ammolite is most typically a two-dimensional gem, united with its matrix of petrified sediment. A loose pearl would first have needed to survive the decomposition of the mollusk to be enveloped in the protective sediment, and then only the outermost layers of aragonite would be preserved. The ammolite pearl, if it existed, would be lost in the midst of the rock that forms the interior of a potentially priceless ammonite fossil.

But it would be beautiful in its maker's eyes.

Update: I visited a lease on the Bear Paw Shale in Southern Alberta last summer. This is within what is commonly known as the K-zone. A massive area, where shells have been crushed and/or flattened by subsequent layers of overburden. I discovered three specimens which are important to this discussion. Specimen 1, is an ammonite with considerable shell damage from a predator attack. Clearly, these are mainly blister type pearls, but several present as singular loose pearls. Although the pearls themselves have since been replaced, there is an a convex aragonitic surface with andate margins. I've also attached images of replaced pearls, selected for their immediate proximity to the aragonitic surface of the shell itself.

These were found at the waterline of the river. The ammonite had rolled downhill, smashing to bits yet the debris field remained within a small range. In retrospect, reconstruction proved more ideal than destruction. After all there was no need to smash otherwise intact fossils.

Upon cursory examination, it's apparent ammonites are much larger than the pearl oysters utilized in today's aquaculture. Specimens of 10-20x larger are typical and as such, the size of pearls is directly proportional. Specimen 2 contained several spherical concretions, consistent with Steve's speculation. Likewise, Specimen 3 demonstrates a single concretion.

Alberta has very strict regulations governing fossils. Having unearthed these samples at a shell agreement site, we were duly bound to report and apply to the Royal Tyrell Museum for a disposition. Needless to say, the senior paleontologists would deny the application.

The email read:


Thank you for your email. Sorry for the delay in getting back to you but I wanted to check a few things before responding. Based on the information provided in your email and what appears to be an overall absence of fossil pearls in our collection, it is unlikely that Disposition would be issued for the fossils in question.

Given your scientific interest in the fossils, the fossils can be deposited here and given Royal Tyrrell Museum (RTMP) accession numbers that can then be used by you and your team when publishing your results. I recommend contacting our Collections Manager, Brandon Strilisky (cc’d on this email) to discuss the details for dropping the fossil off, getting accession numbers and details for moving forward with the scientific study of the fossil. It is our policy to include all relevant collector and/or finder information in our Collections database.

It may also be useful for you or one of your research team members to visit our collections to see if there are pearls associated with any specimens already catalogued here. It is possible that we have pearls in our collection but they haven’t been recognized, yet.

Please let me know if you have any questions.


Dan Spivak
Head, Resource Management Program

Royal Tyrrell Museum of Palaeontology

T: 403-823-7707 | F: 403-823-7131
Box 7500, Drumheller, Alberta T0J 0Y0 Canada

Although they'll retain the lot, I'm the namesake of the discovery by record. Joined by the invitation to collaborate with museum identifying pearls which may already be in the collection. This is a terrific opportunity, especially in light of Covid-19 and it's imposed austerity measures.

For the moment it's prudent to remain skeptical, despite the appearance of one and two adding up. These specimens need closer scrutiny on many levels to be certified.

I've been invited back to the shell agreement next season. There will two challenges. The first, determining a rate of incidence. The second, discovering a true ammolite pearl. That being the discovery of an aragonitic concretion by the reformation of it's own natural structure. At that time, I'm also planning to visit the RTM collection to examine "Blue Zone" fossils. This is very important because this is the zone which produces entire, high quality specimens. I doubt I'll be allowed destructive testing, so it will be incumbent upon me to be highly objective while examining the external integrity of specimens.


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Dave, quite the way to bump the thread! I'll be following.

The Alberta paleontologists might be interested in the precedent of Kieslinger's Triassic Nautilus blister (specimen never traced despite my best contacts at the time).