Nonclastic rocks are sedimentary rocks that do not have a clastic texture. They are formed by chemical precipitation or organic processes rather than by compaction and cementation of fragments. There are several synonyms for nonclastic rocks that are frequently used in the field of geology. These include chemical rocks, organic rocks, and biochemical rocks. Chemical rocks are formed by the precipitation of minerals that have dissolved in water. Organic rocks are formed from the remains of living organisms, such as shells and bones. Biochemical rocks are similar to organic rocks but are formed by the actions of microorganisms. Understanding the different types of nonclastic rocks is important for interpreting the geological history of an area.