* The Earth formed around 4.54 billion years ago.
* The oldest known rocks on Earth are about 4 billion years old.
This means that rocks have been around for almost the entire history of our planet. They are constantly being formed, broken down, and reformed through processes like:
* Volcanic eruptions: Create new igneous rocks.
* Weathering and erosion: Break down existing rocks into smaller pieces.
* Sedimentation: Deposit these pieces, which can then be cemented together to form sedimentary rocks.
* Metamorphism: Transform existing rocks through heat and pressure into metamorphic rocks.
So, while we can't say exactly how long rocks have been around, it's safe to say that they have been an essential part of Earth's history for a very, very long time.
