Curator reveals fascinating facts about pearls

[effisk]

I'm afraid I don't have any hi-resolution pics of the ones above. Here's the nautilus one:

About the Strack book and its pictures, there's an illustration that describes a very suprizing (and debatable) process.
I don't have the book with me right now but I remember it's on page 126 or 126, pic #87.
Strack describes an object being expelled through the solid shell. How could such a thing happen? Once the shell is formed, the material is solid and its state cannot change.

I never took the time to ask Strack abouth this illustration. I briefly discussed it with H.Bari who found it surprizing too.

 

[Caitlin]

I recently read about that process, but I forget where, maybe Streeter.

He claims the outer shell is continuously worn away as layers of nacre are deposited on the inside. Otherwise the shells would get thicker and thicker. So a blister pearl that started out between the mantle and the shell will eventually be found coming through the outside of the shell.

I checked out the pages you indicated in Strack. It seems to be the same process So a worm that bores in from the outside who gets way inside the shell will eventually be expelled back through the outside.

I am holding this idea in a holding bag inside my brain until further info is obtained.

I brought this process up in another thread, but can't remember which one.

 

[knotty panda]

Kidney stones are pearls if you want to get technical....LOL

I'm not so sure of that. Where's the irritant?

 

[effisk]

He claims the outer shell is continuously worn away as layers of nacre are deposited on the inside. Otherwise the shells would get thicker and thicker. So a blister pearl that started out between the mantle and the shell will eventually be found coming through the outside of the shell.

Does the illustration show this on the Strack book? It just seemed that the irritant was migrating through the shell, but what you describe makes more sense. Thanks.

 

[Hanaleimom]

Thank you, effisk. The pictures are amazing. I like the shells too.