Rock, the main object of geological exploration. It is a solid mineral or mineral mixture, in which the rocks under the sea surface are called reefs, submerged reefs and shoals, and it is an aggregate of one or more minerals with a certain structure, and a few of them contain biological remains or remains (that is, fossils). Minerals have three states: solid (such as fossils), gaseous (such as natural gas) and liquid (such as oil), but they are mainly solid substances, which are one of the materials that constitute the earth's crust and the main component of the earth's lithosphere.