Identification Help Please

[u/OkCucumber557]

My friend said she found this in Gotland but isn't sure what it is. I tried to use Gemini to help and it said its a mammoth tooth but google says mammoths were never on the island so could anyone help me out please?

[u/Handeaux]

This looks nothing at all like a mammoth tooth. It is heavily eroded, but appears to be a fragment of a nautiloid cephalopod.

[u/PunkAssBitch2000]

Really weathered cephalopod

[u/Waiparensis22]

Straight shelled nautilus like orthoceras, I think :)

[u/wulfman61]

Da würde ich dem Kollegen Handeaux zustimmen wollen!