What is Wüstite?
Wüstite is the iron(II) oxide mineral FeO, a high-temperature oxide found in reducing environments, metallurgical systems and some meteorites.
Mineralogy and structure
Reference formula: FeO. Wüstite is cubic but commonly non-stoichiometric, with vacancies and variable Fe3+ content. COD 9002669 is used as a labelled representative Fe-rich model rather than an ideal claim for every specimen. Wüstite is classified with oxides and has cubic crystal symmetry. Typical hardness is 5–5.5 on the Mohs scale and specific gravity is approximately 5.5–5.9.
Colour, lustre and habit
Typical colours include black, grey, brown-black, greenish-black. The usual granular, massive, microscopic habit and metallic, sub-metallic, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Wüstite forms in or is associated with reduced magmatic rocks, meteorites, iron-rich slags and high-temperature industrial or experimental environments. Important documented localities include meteorites, iron deposits, industrial slags and high-temperature experimental assemblages worldwide.
Iron oxide from a reducing environment
Wüstite is a specialist mineral with a strong materials-science and meteorite connection. Its value comes from documented formation conditions rather than bright colour.
Collecting and care
Avoid dust and grinding; keep dry, label industrial or meteoritic origin and do not assume a black oxide is wüstite without analysis.
