Since all of the solid parts of the universe are composed of minerals, it is truly a fundamental science of far-ranging importance.
Rocks are usually aggregates of minerals which can be physically separated from one another.
It is important to note that a mineral's composition need not always be fixed. The mineral olivine, for example, may vary in composition from Mg 2 SiO 4 to Fe 2 SiO 4 . This is the most fundamental property of minerals. One could match the chemical composition of a mineral by mixing the appropriate amounts in elements and making it into a homogeneous solid. From this definition, it is apparent that mineralogy relates chemistry and physics to geologic materials.