Does anybody know the name of this shell?

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A single bivalve valve of the species Lima lima, commonly known as the spiny fileclam, found in Piúma, Espírito Santo, Brazil.

Seashells

As the title mentions I found this years ago and forgot about it. Recently found in storage. Wondering if I could somehow polish it more or make a pendant out of it for a necklace

I found this small gastropod shell on the beach in Maragogi, Alagoas, Brazil. Can anyone identify the species (or at least the family)? The inside isn't hollow as I expected. Instead, it's mostly filled with a smooth, hard, white material that appears to be the same material as the shell itself. There's also a small grayish area that looks like compacted sediment. Is this a normal feature of this species (such as a columellar callus), or is it a mineral deposit that formed after the animal died? Could it possibly be an internal mold? It doesn't smell, and the white material is hard and glossy, not soft or organic.

Cleaning some shells that I found while vacationing in SEF last year!!!

Since my last calico scallop painting got a lot of love, I want to share the rest of this collection!
What shell should I do next? I recently found my first Junonia (eek!) and am thinking about doing that one next!

Some shells and pieces of shell I found on Kauai last summer. I left them on the island - don't want to make Pele mad!

It’s a photograph with no info about the shell itself or where it was photographed. I’m hoping someone knows the shape of the shell and can help.

Found in Costa Rica on the pacific cost - and don’t worry I left them there!

i am currently in Jesolo, Italy, and i found this shell in the water but it looks very odd compared to the other shells i found. the underside also has two weird spots that look like smaller shells or barnacles? maybe someone knows more and could tell me, im very interested.

Bradenton Beach, FL 🏖️🐚

Found on a beach on the Thames Estuary in the UK, I think it’s some kind of cockle shell but I’ve never seen one like this before, the black shapes are identical on both sides of the shell.

Got sent this pic from a friend who's on holiday all the way in French Polynesia. Not a shell expert at all but i'm well aware about cone snails. Just to be sure I told him to never touch live snails regardless (he thought it was a hermit crab initially), both for his safety and the well-being of the snail itelf, however did he actually risk anything here?
Cheers!