The second type of sediments deposited through precipitation from solution are called chemical deposits. The last type is organic deposits which involve activity of organisms. Clastic rocks usually pass through four distinct stages of formation of rock. The first stage is disintegration of original rock to generate fragments. This is followed by transportation of fragments to the site of accumulation.
Third stage is deposition itself followed by lithification.
Lithification is compaction of loose sediments into solid rock. Rocks of chemical and organic origin usually go through the last two stages only. Commonly we get rocks like sandstone , shale , conglomerate through clastic processes. Metamorphism Metamorphism is the process of chemical and physical alteration of a rock in solid state. Usually a rock is stable in a range of temperature and pressure that is close to the conditions prevailing at the time of their formation.