Maghemite forms by weathering or low-temperature oxidation of spinels containing iron(II) such as magnetite or titanomagnetite.

Maghemite can also form through dehydration and transformation of certain iron oxyhydroxide minerals, such as lepidocrocite and ferrihydrite.

Maghemite was named in 1927 for an occurrence at the Iron Mountain Mine, northwest of Redding, Shasta County, California.

There is experimental[8] and theoretical[9] evidence that Fe(III) cations and vacancies tend to be ordered in the octahedral sites, in a way that maximizes the homogeneity of the distribution and therefore minimizes the electrostatic energy of the crystal.

[9] Maghemite exhibits ferrimagnetic ordering with a high Néel temperature (~950 K), which together with its low cost and chemical stability led to its wide application as a magnetic pigment in electronic recording media since the 1940s.

[11] Maghemite nanoparticles are used in biomedicine, because they are biocompatible and non-toxic to humans, while their magnetism allows remote manipulation with external fields.

The presence of the particles indicated that they are suspended for long periods due to poor ventilation, particularly on platforms.