Goethite

Formula: α-Fe3+O(OH)

Colour: Brownish black, yellow-brown, reddish brown

Lustre: Adamantine, Silky, Metallic, Dull

Hardness: 5 – 5½

Specific Gravity: 4.27 – 4.29

Crystal System: Orthorhombic

Member of: Diaspore Group

Name: Named in 1806 by Johann Georg Lenz in honor of the German poet, novelist, playwright, philosopher, politician, and geoscientist Johann Wolfgang von Goethe [August 28, 1749, Frankfurt, Germany – March 22, 1832, Weimar, Germany]. Goethe was Chief Minister of State of Weimar. (Portions of the Goethe mineral collection are reputedly held by the Goethe Society in New York, New York – USA.)

Type Locality: Hollertszug Mine (Hollerter Zug Mine), Dermbach, Herdorf, Daaden-Herdorf, Altenkirchen District, Rhineland-Palatinate – Germany

Polymorph of: Feroxyhyte, Lepidocrocite, UM1985-08-OH:Fe

The most common simple iron oxide mineral. A weathering product of numerous iron-bearing minerals.