These are certainly pearls stuck to other pearls. Only pearls stuck to the shell are described as mabes and usually exclusive to a cultural setting. Blister pearl is more common in natural settings. Instead these grow along the shell as opposed to to/from it. These were formed in a perforation of the pallial mantle. The thin membrane that builds the shell.
There is more going on here, though. This shell has suffered a blunt force. Image 3 clearly shows multiple small fragments concreted in an elegant nacreous matrix. Typically each fragment lined in black periostracial protein. Likewise, a complete circle of radiating growth fronts outward to the circumference. Very nice piece!
In Images 1 and 2 we see a large textured pearl attached to other pieces. Individually, nice pearls, but at some time in their life were erupted then become lodged within another space. The remaining images present holes where no holes ought to be. This also evidences predator attacks, likely other gastropods, namely predatory snails.
Broken parts does not detract from this specimen. Instead supports this creature endured and survived multiple environmental stresses.
Value-wise, we don't discuss dollars much here, because it's too subjective. It's definitely a lucky piece, after all who gets to say that? Scientific value some, though not a rare piece and something I observe in abalone and fossils often.
An interesting piece and I thank you for sharing it with us.
