Magnetic mineralogy

Important regions on the diagram include the titanomagnetites, which form a line of compositions Fe3−xTixO4 for x between 0 and 1.

The titanomagnetites have an inverse spinel crystal structure and at high temperatures are a solid solution series.

Crystals formed from titanomagnetites by cation-deficient oxidation are called titanomaghemites, an important example of which is maghemite.

The other important class of strongly magnetic minerals is the iron sulfides, particularly greigite and pyrrhotite.

As the proportion of iron decreases, the crystal structure changes from bcc to face centered cubic (fcc).