A sedimentary rock is formed from the accumulation and cementation of mineral and organic particles over time. These rocks often originate from weathering and erosion processes that break down pre-existing rocks into smaller fragments, which are then transported by water, wind, or ice. As these sediments settle in layers, they become compacted and solidified through natural processes, creating various types of sedimentary rocks such as sandstone, limestone, and shale. Sedimentary rocks are important for understanding Earth's history, as they often contain fossils and can reveal information about past environmental conditions.