This is a brick pebble that's been softened by rolling around in the sea awhile. You might also find yellow or red ochre, softer muddy pieces of shale, marls, & chalks you could do this with - depends where you are.
Somebody's dog came to say hi at the end 😂
We left the pebbles on the beach...
Small joys in a fkd up world:
Misty by the sea this aft. I love a soft misty day.