What is exfoliation and what types of rock is it most common in?

Exfoliation is a geological process in which layers of rock peel away from a larger mass, often due to the release of pressure from overlying materials or temperature changes. This process is most common in igneous rocks, particularly granite, where the outer layers expand and contract more than the inner layers, leading to the formation of thin, flake-like sheets. Exfoliation is commonly observed in mountainous regions where erosion has removed the overburden.