I'm hoping someone can help identify the item in the pictures below. We were out looking for sharks teeth at Walton-on-the-Naze in Essex and whilst we didn't find anything that day, I did pick this item up. We originally thought it was a pumice stone, but having checked, I'm not so sure now.
It's approximately 21cm long and 15cm down, is quite light (which is why we thought it was pumice) and is full of tiny holes. The second image hopefully shows them a bit better. I can provide an accurate map position as to where it was found if needed and also other photos if different angles would help.
I have no doubt it is worth millions and I can retire early