This flint axe was found in 1912 in West Tofts, a now-abandoned village in the UK between Cambridge and Norwich, It was made by a Homo heidelbergensis or possibly a Neanderthal, somewhere between 300,000 and 500,000 years ago.
This kind of tool is fairly common throughout western Europe and Africa, but this specimen is unique for having a Cretaceous-era fossil of a spiny oyster in the centre that suggests the axe's maker wanted the shell on it as an adornment.
It's kept in the Museum of Archaeology and Anthropology at the University of Cambridge, and you can see more details on their web site.
The hand axe. Here's a photo. Also, I did specify "tool" and not "fossil."
A picture is what I was hoping for - thank you! That is gorgeous. Interesting that it's much flatter on that one edge.
It's almost ergonomic, which makes sense. Crazy to me that I never lost it; I used to keep it in my glove box as a lucky charm. Now it's at home on a shelf.