Countermark

Hey there kiddo! So have you ever heard of a countermark?

Basically, a countermark is a stamp that is put onto a coin or other valuable object to show that it is authentic. It's like a secret code that only experts know about.

Let's say you have a shiny gold coin. Someone might try to make a fake gold coin that looks just like yours. But if your coin has a special countermark on it, then people will know that it's the real deal.

Countermarks can be all sorts of shapes and designs. Sometimes they look like letters or numbers, and other times they might be a picture or symbol.

So the next time you see a coin with a funny mark on it, you'll know that it's a countermark and it means that the coin is real and valuable. Cool, huh?