The soup stone is missing. My grandpa was from Vilnius which was part of Poland when he left. They always had soup on the stove every day all day and one of the things in it was always a stone to hold something (herbs?) at the bottom. It was such a part of the family that they weren't sure who was going to inherit the stone - it went to the oldest son.
Maybe it was actually one of these? https://en.wikipedia.org/wiki/Stone_Soup
What kind of stone was it? In Oaxaca Mexico, there is caldo de piedra (literally stone soup) which involves heating up a riverstone really hot and dropping it into a bowl of your ingredients to get it to immediately boil
Of course you have to know which type of stone to use as many can explode when put into a fire.
These stones are also carefully selected and passed down through generations.