Mineralogy and petrology are the intertwined geological sciences dedicated to studying Earth's fundamental materials. Mineralogy focuses on the chemical composition, crystal structure, and physical properties of minerals, the naturally occurring, inorganic building blocks of our planet. Petrology applies this knowledge to understand the origin, composition, distribution, and history of rocks—the aggregates of these minerals—classifying them into igneous, sedimentary, and metamorphic types. Together, these disciplines provide the essential framework for deciphering the processes that form and transform Earth's crust and mantle, from volcanic eruptions to the immense pressures of mountain-building events.