Goethite

Goethite Locality: Dreamtime Mine, Crystal Peak area, Teller County, Colorado Specimen Size: 7.7 x 4.5 x 3.8 cm (small cabinet) Largest Goethite Crystal: 2.1 cm © minclassics
Chemical Formula: FeO(OH)
Locality: Mesabi district, Minnesota, USA.
Name Origin: Named after the German poet, J. W. Goethe (1749-1832).Goethite (FeO(OH)),  named after the German polymath and poet Johann Wolfgang von Goethe (1749–1832), an iron bearing hydroxide mineral of the diaspore group, is found in soil and other low-temperature environments. Goethite has been well known since ancient times for its use as a pigment (ochre). Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France. It was first described in 1806 for occurrences in the Hollertszug Mine, Dermbach, Herdorf, Siegerland, Rhineland-Palatinate, Germany.In 2003, nanoparticulate authigenic goethite was shown to be the most common diagenetic iron oxyhydroxide in both marine and lake sediments.

Physical Properties

Cleavage: {010} Perfect, {100} Distinct
Color:  Brown, Reddish brown, Yellowish brown, Brownish yellow, Ocher yellow.
Density: 3.3 – 4.3, Average = 3.8
Diaphaneity: Subtranslucent to opaque
Fracture: Hackly – Jagged, torn surfaces, (e.g. fractured metals).
Hardness: 5-5.5 – Apatite-Knife Blade
Luminescence: Non-fluorescent.
Luster: Adamantine – Silky
Streak: yellowish brown

Photos :

Goethite with “Onegite” Locality: Dreamtime Mine, Crystal Peak area, Teller County, Colorado Specimen Size: 6.7 x 4.2 x 3.1 cm (small cabinet) Largest Goethite Crystal: 1.7 cm © minclassics
Iridescent Goethite    Cerro Colorado, Minas de Rio Tinto, Minas de Riotinto, Huelva  Spain (±1985) Specimen size: 5.8 × 5.3 × 2.7 cm = 2.3” × 2.1” × 1.1”  © Fabre Minerals
Goethite Locality: Wigwam Creek, Jefferson County, Colorado Specimen Size: 4.0 x 2.5 x 2.4 cm (miniature) © minclassics
Goethite Locality: C. G. Coil claim on Goethite Hill, near Lake George, Park County, Colorado Specimen Size: 5.2 x 4.8 x 4.7 cm (small cabinet) Largest Goethite Crystal: 2.7 cm © minclassics
En Bournegade (Embournegade), Alban – Curvalle, Alban – Le Fraysse area, Tarn, Midi-Pyrénées, France © Jean-Marie LAURENT
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