The correct answer is Petrology. Rocks are the materials that form the essential part of the Earths solid crust. œRocks are hard mass of mineral matter comprising one or more rock forming minerals. Rocks are formed from the molten material known as magma. The study of rocks is called Petrology (in Greek, petra means rock, logos means science). Petrology deals with the description of rocks. Petrogenesis is the study of the origin of rocks.