The discipline of geology known as petrology investigates rocks and the conditions in which they develop. Igneous, metamorphic, and sedimentary petrology are the three types of petrology. Because both igneous and metamorphic petrology makes extensive use of chemistry, chemical techniques, and phase diagrams, they are frequently taught together. Sedimentary petrology, on the other hand, is frequently taught alongside stratigraphy because it is concerned with the processes that lead to the formation of sedimentary rock. Mineralogy, petrography, optical mineralogy, and chemical analysis are all used in petrology to explain the composition and texture of rocks. Petrologists also employ geochemistry and geophysics principles to better understand the origins of rocks by studying geochemical patterns and cycles, as well as thermodynamic data and experiments.