Magnetic minerals occur in different geological processes and play a crucial role in the rock magnetism. In igneous rocks, minerals such as magnetite are formed from cooling magma and may contain spinel grains in the magnetite. These magnetite crystals, rich in iron oxides, are responsible for the mineral magnetism of the rock. These magnetic materials can be affected by the Verwey transition at high temperatures, which affects saturation magnetization and coercivity (Hc). When the temperature approaches the Curie temperature (Tc), the magnetic remanence of these minerals changes, which provides important information about the formation conditions.

In sedimentary settings, magnetic minerals including titanomagnetites and other oxides of iron are transported by natural processes including wind and water and settle down in layers that form part of the environmental magnetism. In the course of time, chemical transformations, for instance, oxidation of Fe-bearing minerals, may affect ilmenite and hematite and change the grain shape and mineralogy. These processes influence the degree of coercivity and the crystal structure of magnetic minerals, which in turn helps to understand the history of geomagnetic fields and the conditions under which the rocks were formed.