Clastic rock is a type of sedimentary rock formed from the accumulation and cementation of fragments, or clasts, of pre-existing rocks. These fragments can vary in size, ranging from tiny clay particles to large boulders. Common examples of clastic rocks include sandstone, shale, and conglomerate, each classified based on the size of the clasts they contain. The formation of clastic rock typically occurs through processes like weathering, erosion, and deposition. Over time, sediments are compacted and cemented together by minerals, creating solid rock. Clastic rocks are important for understanding Earth's history, as they often contain fossils and provide insights into past environments.