titanomagnetit

Titanomagnetite is an oxide mineral in the spinel group that represents a continuous solid-solution series between magnetite (Fe3O4) and ulvöspinel (Fe2TiO4). Its general formula can be written as Fe3−xTixO4, with titanium substituting for iron in the lattice and charge balanced by adjustments in iron’s oxidation states. Natural titanomagnetites span from magnetite-rich compositions toward Ti-rich endpoints, and many crystals show exsolution textures where magnetite- and ilmenite-rich lamellae are intergrown as they cool.

In terms of structure, titanomagnetite is an inverse spinel. Titanium typically substitutes in the octahedral (B) sites, influencing the distribution of iron between Fe2+ and Fe3+ and affecting mineral stability and color. The solid-solution nature means the exact composition can vary widely within the same rock, reflecting the magmatic differentiation history of the system.

Titanomagnetite occurs most commonly in mafic to ultramafic magmatic rocks and in layered intrusions, where it forms during crystallization from silicate melts. Upon slow cooling, titanomagnetite often exsolves into magnetite- and ilmenite-rich lamellae, a texture that is widely used as a magnetic and geological indicator of magmatic processes.

Economically, titanomagnetite ores are important in some iron ore districts. The titanium content within titanomagnetite can influence processing routes, and such ores may also be sources of Fe-Ti compounds or Ti-bearing concentrates used for pigment production and other industrial applications. Titanomagnetite thus serves as both a petrographic marker of magmatic evolution and a practical ore mineral.