* The Earth's Crust: The outermost layer of the Earth is called the crust, and it's composed of mostly igneous, sedimentary, and metamorphic rocks. While granite is a common type of igneous rock found in the crust, it's not the only type.
* Crust Thickness: The crust is much thinner than 25 miles. It varies in thickness depending on location:
* Oceanic Crust: Around 3 to 6 miles thick.
* Continental Crust: Around 20 to 30 miles thick.
* The Mantle: Beneath the crust lies the mantle, a much thicker layer (about 1800 miles) made of mostly solid rock, but it behaves like a very viscous fluid over long periods.
In summary: The Earth doesn't have a granite skin. The crust is a complex layer made of various rock types, with varying thickness depending on location.
