an oxide of iron.
A hydrous oxide of iron (HFeO2), occurring in prismatic crystals, also massive, with a fibrous, reniform, or stalactitic structure. The color varies from yellowish to blackish brown.
an oxide mineral with the chemical formula of alpha-FeO*OH
A yellowish, reddish, or brownish-black mineral, with the chemical formula FeO(OH). Goethite commonly forms as a weathering product of iron ore.
Goethite, named after the German polymath Johann Wolfgang von Goethe, is an iron bearing oxide mineral found in soil and other low temperature environments. Goethite has been well known since prehistoric times for its use as a pigment. Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France.