Editing Goethite (section)

{{Short description|Iron(III) oxide-hydroxide named in honor to the poet Goethe}}
{{Infobox mineral
| name        = Goethite
| category    = [[oxide minerals]] hydroxide subgroup
| image       = Goethite-169735.jpg 
| caption     = 
| formula     = α-[[Iron|Fe]][[Oxygen|O]]([[Hydroxide|OH]])
| IMAsymbol   = Gth<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref>
| molweight   = 
| strunz      = 4.FD.10
| system      = [[Orthorhombic]]
| class       = Dipyramidal (mmm) <br/>[[H–M symbol]]: (2/m 2/m 2/m)
| symmetry    = ''Pbnm''
| color       = Yellowish to reddish to dark brown or black
| habit       = radial acicular, mammillary, botryoidal, stalactitic, massive, as encrustation, as pseudomorph; may be banded or iridescent 
| twinning    = 
| cleavage    = Perfect {010}
| fracture    = Uneven to splintery
| mohs        = 5.0–5.5
| luster      = Adamantine to dull
| refractive  = Opaque to sub-translucent
| opticalprop = 
| birefringence = 
| pleochroism = 
| streak      = Brown, brownish yellow to orange yellow
| gravity     = 3.3–4.3
| density     = 
| melt        = 
| fusibility  = Fusible at 5–5.5
| diagnostic  = 
| solubility  = HCl soluble
| diaphaneity = 
| other       = weakly magnetic
| references  = <ref name=HurlbutKlein1985>{{cite book |last1=Hurlbut |first1=Cornelius S. |last2=Klein |first2=Cornelis |year=1985 |title=Manual of Mineralogy |edition=20th |publisher=Wiley |isbn=0-471-80580-7 |url-access=registration |url=https://archive.org/details/manualofmineralo00klei }}</ref><ref name=Barthelmy2012>{{cite web |last1=Barthelmy |first1=David |title=Goethite Mineral Data |url=http://webmineral.com/data/Goethite.shtml |website=Mineralogy Database |access-date=8 April 2022 |date=2012}}</ref><ref name=Mindat>{{mindat|title=Goethite|id=1719}}</ref><ref name=HOM>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Goethite |url=http://www.handbookofmineralogy.org/pdfs/goethite.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.handbookofmineralogy.org/pdfs/goethite.pdf |archive-date=2022-10-09 |url-status=live |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=14 March 2022 |date=2005}}</ref>
}}
[[File:Goethite-182557.jpg|thumb|upright|Unusual specimen of goethite replacing a [[gypsum]] [[stalactite]]; the center is hollow. From [[Santa Eulalia, Chihuahua]], Mexico.]]
'''Goethite''' ({{IPAc-en|ˈ|ɡ|ɜːr|t|aɪ|t}},<ref>{{Cite dictionary |url=http://www.lexico.com/definition/goethite |archive-url=https://web.archive.org/web/20210805045033/https://www.lexico.com/definition/goethite |url-status=dead |archive-date=August 5, 2021 |title=goethite |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]]}}</ref><ref>{{cite Merriam-Webster|goethite}}</ref> {{IPAc-en|usalso|ˈ|ɡ|oʊ|θ|aɪ|t}}<ref>{{cite Dictionary.com|goethite}}</ref><ref>{{cite American Heritage Dictionary|goethite}}</ref>) is a mineral of the [[diaspore]] group, consisting of [[iron(III) oxide-hydroxide]], specifically the α-[[Polymorphism (materials science)|polymorph]]. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient times for its use as a [[pigment]] (brown [[ochre]]). Evidence has been found of its use in paint pigment samples taken from the [[Lascaux|caves of Lascaux]] in [[France]]. It was first described in 1806 based on samples found in the Hollertszug Mine in [[Herdorf]], [[Germany]].<ref name=Mindat/> The mineral was named after the [[Germany|German]] [[polymath]] and poet [[Johann Wolfgang von Goethe]] (1749–1832).