Minerals are the basic building blocks of all rocks.
Many minerals have economic value. Many minerals are important in modern industry, health and political activities. A knowledge of mineralogy is required for an understanding of rocks, and hence for an understanding of how the earth and other planets operate. Virtually all aspects of geology are fundamentally tied to mineralogy. With Roentgen's discovery of X-rays in 1895, the stage was set to study minerals on a molecular or atomic scale.