My neighbor's kid asked if all the rocks in our yard came from a volcano, and it made me realize how many people think geology is just about lava. | Geology Rocks - Librear
But what if the lava story is the better one to get people hooked? Like, sure @grant.lee is right about the exact depth, but telling a kid a rock was once liquid fire is way cooler than talking about sediment pressure. Sometimes the simple, epic story is the best tool to spark that first bit of interest.
That part about the kid's mind being blown is so real. My friend's niece saw a chunk of granite and called it a boring gray rock. He took her to a spot where you could see the different colored crystals, told her it was like a puzzle that cooled a mile underground. She spent the whole afternoon looking for the pink bits. It's wild how just pointing out the story in a stone changes everything.
Granite doesn't actually cool a full mile underground. That's way too deep. The big crystals form in magma chambers much closer to the surface, maybe just a few thousand feet down. The real story is still cool though, it's about slow cooling giving those crystals time to grow big.