Editing Goethite (section)

== Distribution ==
Goethite is found all over the planet, usually in the form of [[concretion]]s, [[stalactite|stalactitic]] formations, [[oolite]]s (a form consisting of tiny round grains cemented together),<ref name=Mindat/> reniform (kidney shapes) or botryoidal (globular, like bunches of grapes) accumulations. It is also a very common pseudomorph. It is frequently encountered in the swampy areas at the head of spring waters ('[[bog iron]]'), on cave floors, and on the bottom of lakes and small creeks. The ''boxworks'' or [[gossan]] resulting from the [[oxidation]] of sulfide ore deposits is formed of goethite along with other iron oxides and quartz.<ref name=Sinkankas1964>{{cite book |last1=Sinkankas |first1=John |title=Mineralogy for amateurs. |date=1964 |publisher=Van Nostrand |location=Princeton, N.J. |isbn=0442276249 |pages=342–344}}</ref><ref name=HurlbutKlein1985/>

Significant deposits of goethite are found in [[England]]; [[Cuba]]; and [[Minnesota]], [[Missouri]], [[Colorado]], [[Alabama]], [[Georgia (U.S. state)|Georgia]], [[Virginia]], and [[Tennessee]], in the [[United States]].<ref name=Sinkankas1964/><ref name=HurlbutKlein1985/>

Deposits significant in location, if not in abundance, have been found in the [[Mars|Martian]] crater [[Gusev (Martian crater)|Gusev]] by NASA's ''[[MER-A|Spirit]]'' rover, providing strong evidence for the presence of liquid water on the planet in an earlier stage of its evolution.<ref>{{cite journal |last1=Klingelhöfer |first1=G. |last2=DeGrave |first2=E. |last3=Morris |first3=R. V. |last4=Van Alboom |first4=A. |last5=de Resende |first5=V. G. |last6=De Souza |first6=P. A. |last7=Rodionov |first7=D. |last8=Schröder |first8=C. |last9=Ming |first9=D. W. |last10=Yen |first10=A. |title=Mössbauer spectroscopy on Mars: goethite in the Columbia Hills at Gusev crater |journal=Hyperfine Interactions |date=November 2005 |volume=166 |issue=1–4 |pages=549–554 |doi=10.1007/s10751-006-9329-y|bibcode=2005HyInt.166..549K |s2cid=95186141 |url=https://biblio.ugent.be/publication/538524/file/538971 }}</ref>

[[Limpet]]s' teeth are composed of about 80% goethite fibres of only tens of nanometers in diameter, small enough to be [[monocrystalline whisker|flaw-insensitive]], which accounts for their extreme [[tensile strength]] of 3.5–6.0&nbsp;GPa and [[elastic modulus]] of {{val|120|30|u=GPa}}.<ref name="BBCLimpet">{{cite web | url=https://www.bbc.co.uk/news/science-environment-31500883 | title=Limpet teeth set new strength record | publisher=[[BBC]] News | work=BBC News: Science and Environment | date=18 February 2015 | access-date=23 December 2016 | author=Webb, Jonathan}}</ref><ref>{{Cite journal
|title=Extreme strength observed in limpet teeth
|first1=Asa H.|last1=Barber
|first2=Dun|last2=Lu
|first3=Nicola M.|last3=Pugno
|date=2015-04-06
|doi=10.1098/rsif.2014.1326
|publisher=[[Royal Society]]
|journal=J. R. Soc. Interface |volume=12 <!-- not shown‽ -->
|issue=105
|at=20141326
|doi-access=free
|pmid = 25694539
|pmc = 4387522
}}</ref>