Okay kiddo, have you ever seen a really big building, like a castle or a cathedral? Well, sometimes the stones on the bottom of the building are a little different than the ones on the top. They might be bigger or stronger, because they have to hold up the whole building!
One kind of stone that's really good for this is called bargate stone. It's a special kind of sandstone that comes from a place called the Bargate Formation in England.
The thing that makes bargate stone so strong is that it has a lot of iron in it. Iron is a really tough metal, and it helps hold the stone together really well. When people build things with bargate stone, they know they can rely on it to be strong and durable for a long time.
So, that's what bargate stone is all about. It's a special kind of rock that people use to build really strong and sturdy buildings.