Seems there’s many a story like this - even I have one!
When I lived in Egypt, I spent a summer interning at the US consulate in Cairo. At one point, a package addressed to the consulate arrived from the US. In it was a Smuckers jam jar full of sand, and a letter from a US citizen who’d traveled to Egypt years prior and had taken the sand from Giza and around the pyramids as a souvenir. Over the next several years they’d suffered from considerable misfortune and an overall string of bad luck they were convinced was the result of having been cursed for stealing sand from the pyramids. They were asking us to return the sand to the pyramids and end the “pharaoh’s curse” they’d brought down on themselves.
I only interned at the consulate for the summer, so this was the only such package received while I was there. Apparently it wasn’t an entirely uncommon occurrence, though - some of the staff at the consulate who’d been there awhile could recall such a thing happening a number of times before. Similarly, when I took an Egyptology course at the American University in Cairo the professor mentioned having received similar packages of sand, bits of stone, chips of pyramids or other ancient temples and such. I suppose folks would just try and mail the material back to whomever they felt was their best option to have it returned.
We sort of laughed it off, but someone did indeed take the sand back and pour it out in Giza - whether or not you believe in curses it’d just be downright mean to not return it and sentence that person to a cursed lifetime just in case. I think someone even wrote a letter back to them to let them know it was returned.
Picture, memories, and maybe a fridge magnet. Otherwise, be careful!