Shell Artifact?

[Florida Finder]

Hello everyone. I hope y’all had a great Christmas!
Most times I’m digging for Seminole Indian war relics but from time to time an Indian relic turns up on accident. Today I didn’t find and war relics but while digging an old iron nail this shell artifact turned up. Any ideas on its purpose would be appreciated.

 

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[Fat]

...plz make more pics, both sides, up and down, side to side. I don’t see anything other than natural...

 

[Tdog]

Can you tell whether it's water worn? It looks like a water worn shell to me and not an artifact--this smoothed the whole piece. I'd say those lines are indicative of layers that formed as the animal was developing. The hole is from erosion or parasitic activity.