ID Help: Beastly Blister Pearl

[leftylaru]

Hi Everyone,
I'm new to the group, what a great resource. I got this piece as a mystery item along with some

antique/ancient shell beads. It has been drilled, a pendant? It appears old and used. The

surface is worn and has some old discolored shellac or something that has turned brown. The

pearl weighs 134 grams and measures 67mm x 45mm x 38mm. Though the surface is worn, there are

many nacreous areas visible. Any thoughts or help on origin of the pearl, or how and where it

may have lived its previous life?
The bead collection she was selling was her Mother's and most of the items that were marked were

from Burma, India and Mali.
Thanks is advance for any help,
Marc

 

[GemGeek]

That is one scary something!

 

[Lagoon Island Pearls]

What an interesting piece!

The brown coloration as mentioned is likely conchiolin, which falls away from shells when it dries, leaving residual amounts in cracks and depressions.

Two of the five images show rings consistent with cut shell from near the hinge. Otherwise the remaining surfaces present with typical growth fronts.

The specimen was heavily infested (septic) with boring predators, possibly Polydora ciliata.

It's highly calcareous with some nacreous structures present.

The sheer size of this piece eliminates several possibilities, ie gastropods or pectinidae or pteriod.

It's likely heterodonta and marine origin. Possibly Giant, Horse, Gaper or Piddock clam.

 

[pattye]

Welcome and thanks for the great photos, leftylaru!

What a fascinating item! I'm happy we get these unusual pieces along with beautiful, traditional pearls. And soooo glad Dave has an idea what they might be, haha, because I certainly had no idea!

 

[Lagoon Island Pearls]

And soooo glad Dave has an idea what they might be, haha, because I certainly had no idea!

Blisters near the hinge are really common. Likely due to their proximity to the heart. It's the thickest part of the shell and highly calcitic (old growth), but blisters tend to present with juvenile, protein rich surfaces. They're rarely lustrous and generally unattractive, though I think they're every bit as wondrous as fine pearls... perhaps even more so.

I've attached some images that I had on hand, but have hundreds of shells with blisters in the exact same place.

 

[GemGeek]

I wonder how old it is and whether it was considered a good luck charm.

 

[leftylaru]

A few more photos

A few more photos

Thank you all for your interest and info. If it is possible to identify the mollusk, maybe that would help in guessing where this came from.
Dave,
Do the species you mention come from specific areas or are they widespread?

to GemGeek's comment, I am guessing it was an old tribal talisman or charm. But from where?

 

[Orient]

Looks like a blister rather than a blister pearl, but you are bound to get different opinions on that one! As for the mollusk it would be worth checking out whether it is of saltwater or freshwater origin before trying to narrow down the choices. Could be freshwater from the images as they can also grow rather large. Need chemistry to be sure. The second image posted shows the shell/pearl boundary on the side and it looks quite colourful. Could be a haliotis even. Chemistry is the way to go in the short term IMO.

 

[Lagoon Island Pearls]

Dave, Do the species you mention come from specific areas or are they widespread?

Wide spread. These, like most other pearls or blisters can occur anywhere.

Without the entire shell present, it's difficult to identify. Pearls can be any size, but the larger mollusks are more likely to produce concretions like this.