Large and unique Blister Pearl

[Si…]

Hello, I am new to this forum and was wondering if someone can help please?
I found this rather large and unique Blister Pearl on a beach where I live in Jersey, Channel Islands. UK.
I took it to the World Gemological Institute in Hatton Garden, London for them to take a look at and produce a Pearl Report thinking it was a Pearl. Alas it was not, but a very interesting and unique Blister Pearl. Most unusual because of its size and in its hosts complete oyster shell.
The report describes it as Baroque shape, Carat Weight 2349.00 carat and measurements 105 x 65 x 45 mm.
it’s in it’s complete natural state as I found it.
A couple of questions if you don’t mind if anyone can help I would be most grateful. I believe there’s a collectors market out there for Blister Pearls would anyone have any idea on value for such an item? Also should I attempt to polish the inside, if so how should it go about this please?
Kind Regards
Si…

 

[CortezPearls]

Hello there!
This is an unusual blister, but it is also from a non-"beautiful" mollusk species (non nacreous, and beauty is -of course- in the eye of the beholder).
There should be a market out there for collectors... of course! But, where is it? Hard to say!
Its actual worth will be closer to what a given collector will be able to pay or would be willing to pay...and this is truly hard to gauge with the most unusual species.
Many years ago we purchased a large Spondylus calcifer shell with a blister pearl and we paid some $20 American dollars for it. This one is larger so I would have probably have offered $50.
But of course, you will be limited to your "market".
I would keep it, rather than sell it...if just as a unique curiosity.

 

[SteveM]

Agree best in a trophy case.

That oyster went through decades of pure agony! How would WGI have determined the blister's weight?

You express disappointment that it is not a pearl, yet WGI certifies it as a Blister Pearl in their report (?).

In any case, as has been exposed in other recent threads, GIA, IGS and other influential industry entities refer to the non-nacreous concretions from Conch, Melo Melo and the like as "Pearls" (using those dreaded "scare" quotes), so the same would apply here.

 

[Si…]

Thank you both for your kind words and opinions and also for taking the time to do so, it is truly appreciated.
I agree it’s a difficult one and I I find it fascinating and love it just for what it is. I wonder how long it was in the making .
Kind Regards
Si…

 

[SteveM]

How would WGI have determined the blister's weight?

Just to answer myself here, measured blister dimensions and cubic density of the shell material would provide the resulting estimate.

 

[Lagoon Island Pearls]

It's definitely an interesting specimen. The stippled surface is certainly unique having radiating columnar growth fronts.

However, I would challenge the "blister" classification. From the limited aspects viewed in the images, it appears to be an attached pearl with a visible surface area geometry greater than 180 degrees. If the onset was external to internal (through the shell) it may have started as a blister, but graduated into a stalked form otherwise known as pedunculated pearl. If it's an internal onset then irrupted from a pearl sac to become attached, it's a conjoined pearl.

I would very much like to examine images of the bottom shell for a point of entry. Likewise to see images along the margin at the point of attachment.

You express disappointment that it is not a pearl, yet WGI certifies it as a Blister Pearl in their report (?).

In any case, as has been exposed in other recent threads, GIA, IGS and other influential industry entities refer to the non-nacreous concretions from Conch, Melo Melo and the like as "Pearls" (using those dreaded "scare" quotes), so the same would apply here.

This piece has a nucleus and concentric growth, thus a pearl. I also suggest the presence of aragonite, albeit minor. Hence nacreous, just not highly. Genus ostrea are unquestionably nacreous in structure.

Both terms (blister and non-nacreous) are much too often used in an all or nothing context. I maintain there almost always exists a middle ground in most molluscan species.

A couple of questions if you don’t mind if anyone can help I would be most grateful. I believe there’s a collectors market out there for Blister Pearls would anyone have any idea on value for such an item? Also should I attempt to polish the inside, if so how should it go about this please?
Kind Regards
Si…

There is a market, but here we tend to not speculate value, after all beauty is in the eye of the beholder.

And no, much like coin collection, do not polish or coat it for any reason. It's best value is as is.

It certainly is a curiosity and I hope you'll show us other images as requested.

Thank you for sharing your piece, experience and documentation.

 

[SteveM]

It's definitely an interesting specimen. The stippled surface is certainly unique having radiating columnar growth fronts.

However, I would challenge the "blister" classification. From the limited aspects viewed in the images, it appears to be an attached pearl with a visible surface area geometry greater than 180 degrees. If the onset was external to internal (through the shell) it may have started as a blister, but graduated into a stalked form otherwise known as pedunculated pearl. If it's an internal onset then irrupted from a pearl sac to become attached, it's a conjoined pearl.

Agree, hoping to see an exterior point of entry image. It's easier to imagine an external onset as otherwise you'd think the oyster would have found some way to expel the irritation. Makes me gag looking at it!

Very interesting surface, everyone should take a close look.

Any speculation on age?

 

[Lagoon Island Pearls]

Agree, hoping to see an exterior point of entry image. It's easier to imagine an external onset as otherwise you'd think the oyster would have found some way to expel the irritation. Makes me gag looking at it!

Very interesting surface, everyone should take a close look.

Any speculation on age?

Yeah I've never seen such a large intrusion v available space, especially in the visceral cavity. It's remarkable how the creature pretty much went full term life expectancy, so it was otherwise healthy. Edible oysters in northern latitudes grow quickly and don't live as long as other molluscs. Slow growth in winter and super accelerated in summer with longer daylight and more food available. It's why they make for excellent food quality, having minimal uptake of heavy metals etc.

I would speculate 8-10 years, if that. A lot of predators are in the intertidal zone not limited to marine creatures. Birds, mammals etc. and there are more dynamics physically (wave action, fresh water lenses) and radical temperature changes (sun, frost, rising tides) than suspended in the water column or benthic zone, hence have thicker shells. Oysters and mussels have coarse shells, thus don't depend on substrate like clams, which have necks with siphons and smooth shells. Clam pearls are much more rare by comparison for all those reasons.

 

[Si…]

Hello all,
Wow I am overwhelmed by your responses and genuine interest, it’s truly humbling, thank you so very much..
Here are some more photos and a video, I hope they help?
If you think it maybe some more than a Blister Pearl, do you think it’s worth getting a second opinion? It’s just that it cost quite a bit getting the report I have by WGI
Kind Regards
Si…

 

[Lagoon Island Pearls]

Here are some more photos and a video, I hope they help?
If you think it maybe some more than a Blister Pearl, do you think it’s worth getting a second opinion?

Thank you for the updated imagery.

It's as I suggested. The pearl formed in the viscera then once excessive in size, burst from the sac then became fused to the shell.

The margin between the shell and the pearl is narrow, thus it's only been affixed for the latter part of it's life.

I'm certain it's a conjoined pearl. There's no need to take it to another lab. Attempting to dislodge this will only damage it. While it's quite unique, it's not gem quality nor practical for uses other than demonstration and a keepsake from a rare encounter. Enjoy it for what it is. I have and am very grateful to you for sharing it with us.

 

[SteveM]

Hello all,
Wow I am overwhelmed by your responses and genuine interest, it’s truly humbling, thank you so very much..
Here are some more photos and a video, I hope they help?
If you think it maybe some more than a Blister Pearl, do you think it’s worth getting a second opinion? It’s just that it cost quite a bit getting the report I have by WGI
Kind Regards
Si…

As for a second opinion, lab certifications are only of value for verification of natural origin, along with informed species conjecture. Neither is applicable in your case. In my view some researcher should be offering you a cost-free avenue for studying the specimen in a non-destructive manner.