What is "gothite"

Gothite \G["o]"thite\, gothite \go"thite\, or Goethite \Goe"thite\, n. [After the poet G["o]the.] (Min.) 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.

n. a red or yellow or brown mineral; an oxide of iron that is a common constituent of rust [syn: goethite]