What is the three major rock groups of conglomerate?

Conglomerate is a type of sedimentary rock, which is one of the three major rock groups, alongside igneous and metamorphic rocks. Sedimentary rocks, including conglomerates, are formed from the accumulation and cementation of mineral and organic particles. Conglomerate specifically consists of rounded clasts larger than 2 millimeters in diameter, cemented together by finer-grained materials. The other two major rock groups, igneous and metamorphic, are formed through processes involving cooling and solidification of magma or alteration of existing rocks under heat and pressure, respectively.