Maghemite (γ-Fe2O3) has an inverse spinel crystal structure like magnetite, with Fe only in the 3+ valence state like hematite. It has a combined name of ‘mag’ from magnetite and ‘hem’ from hematite. Maghemite is the end member that results from complete oxidation of magnetite. ‘Maghemitization’ refers to partial low-temperature oxidation of precursor magnetite or titanomagnetite, which involves conversion from one spinel phase to another. Maghemite is an industrially important functional material, so its magnetism has been studied extensively and is generally well constrained. It has strong magnetism and low magnetocrystalline anisotropy, with low coercivity. Partial oxidation of magnetite produces particles with magnetite cores and maghemite shells with higher coercivities than magnetite or maghemite because of lattice strain at the core–shell interface. Low-temperature cycling of a room temperature saturation remanence produces characteristically humped remanence curves for maghemite. The Curie temperature of ~645°C can be obscured because maghemite is unstable at elevated temperatures and generally inverts to hematite before reaching the Curie temperature.