Editing Olivine (section)

==Identification and paragenesis==
Olivine is named for its typically olive-green color, {{cn span|date=February 2021|thought to be a result of traces of [[nickel]],}} though it may alter to a reddish color from the oxidation of iron.

Translucent olivine is sometimes used as a [[gemstone]] called [[peridot]] (''péridot'', the [[French language|French]] word for olivine). It is also called chrysolite (or ''chrysolithe'', from the [[Greek language|Greek]] words for [[gold]] and stone), though this name is now rarely used in the English language. Some of the finest gem-quality olivine has been obtained from a body of [[Mantle (geology)|mantle]] rocks on [[Zabargad Island]] in the [[Red Sea]].<ref>[http://www.mindat.org/loc-6423.html St. John's Island peridot information and history] at [[Mindat.org]]</ref><ref>{{cite journal |last1=Gubelin |first1=Edward |title=Zabargad: The ancient peridot island in the Red Sea |journal=Gems & Gemology |date=Spring 1981 |volume=17 |pages=2–8 |doi=10.5741/GEMS.17.1.2 |url=https://www.gia.edu/doc/Spring-1981-Gems-Gemology-Zabargad-Peridot-Island-Red-Sea.pdf |access-date=6 February 2021}}</ref>

Olivine occurs in both [[mafic]] and [[ultramafic]] [[igneous rock]]s and as a primary mineral in certain [[metamorphic rock]]s. Mg-rich olivine crystallizes from [[magma]] that is rich in magnesium and low in [[silica]]. That magma crystallizes to mafic rocks such as [[gabbro]] and [[basalt]].{{sfn|Klein|Hurlbut|1985|pp=374-375}} Ultramafic rocks usually contain substantial olivine, and those with an olivine content of over 40% are described as [[peridotite]]s. [[Dunite]] has an olivine content of over 90% and is likely a [[cumulate]] formed by olivine crystallizing and settling out of magma or a [[Vein (geology)|vein]] mineral lining magma conduits.<ref>{{cite book |last1=Philpotts |first1=Anthony R. |last2=Ague |first2=Jay J. |title=Principles of igneous and metamorphic petrology |date=2009 |publisher=Cambridge University Press |location=Cambridge, UK |isbn=9780521880060 |edition=2nd |pages=44, 138, 142, 385}}</ref> Olivine and high pressure structural variants constitute over 50% of the Earth's upper mantle, and olivine is one of the Earth's most common minerals by volume.<ref>{{cite journal|last1=McDonough |first1=W.F. |last2= Rudnick |first2=R.L. |year=1998 |title=Mineralogy and composition of the upper mantle |journal=Reviews in Mineralogy |volume=37 |pages=139–164 |url=https://www.researchgate.net/publication/284507003 |access-date=6 February 2021}}</ref> The [[metamorphism]] of impure [[Dolomite (rock)|dolomite]] or other [[sedimentary rock]]s with high magnesium and low silica content also produces Mg-rich olivine, or [[forsterite]].

Fe-rich olivine [[fayalite]] is relatively much less common, but it occurs in [[igneous rock]]s in small amounts in rare [[granite]]s and [[rhyolite]]s, and extremely Fe-rich olivine can exist stably with [[quartz]] and [[tridymite]]. In contrast, Mg-rich olivine does not occur stably with [[silica]] minerals, as it would react with them to form [[orthopyroxene]] ({{chem2|(Mg,Fe)2Si2O6}}).

Mg-rich olivine is stable to pressures equivalent to a depth of about {{convert|410|km|abbr=on}} within Earth. Because it is thought to be the most abundant mineral in Earth's mantle at shallower depths, the properties of olivine have a dominant influence upon the [[rheology]] of that part of Earth and hence upon the solid flow that drives [[plate tectonics]]. Experiments have documented that olivine at high pressures (12&nbsp;[[GPa]], the pressure at depths of about {{convert|360|km|abbr=on}}) can contain at least as much as about 8900 parts per million (weight) of water, and that such water content drastically reduces the resistance of olivine to solid flow. Moreover, because olivine is so abundant, more water may be dissolved in olivine of the mantle than is contained in Earth's oceans.<ref>{{cite journal|doi=10.1029/2006GL026194|title=Olivine hydration in the deep upper mantle: Effects of temperature and silica activity|year=2006|last1=Smyth|first1=J. R.|last2=Frost|first2=D. J.|last3=Nestola|first3=F.|last4=Holl|first4=C. M.|last5=Bromiley|first5=G.|journal=Geophysical Research Letters|volume=33|issue=15|pages=L15301|bibcode=2006GeoRL..3315301S|hdl=11577/1563853 |url=http://ruby.colorado.edu/~smyth/Research/Papers/Hydrolivine.pdf|url-status=dead|archive-url=https://web.archive.org/web/20170809105549/http://ruby.colorado.edu/%7Esmyth/Research/Papers/Hydrolivine.pdf|archive-date=2017-08-09|citeseerx=10.1.1.573.4309|s2cid=35342757 |access-date=2017-10-26}}</ref>

Olivine pine forest (a [[plant community]]) is unique to Norway. It is rare and found on dry olivine ridges in the fjord districts of Sunnmøre and Nordfjord.<ref>{{cite journal |last1=Brandrud |first1=T.E. |year=2009 |title=Olivinfuruskog og rødlistearter i Bjørkedalen, Volda: naturverdi og forvaltningsmuligheter |journal=NINA Rapport |volume=461 |url=https://brage.nina.no/nina-xmlui/handle/11250/2397756 |access-date=14 February 2021 |language=norwegian}}</ref>

<gallery widths="180px" heights="150px">
File:Papakolea Beach sand high mag 052915.jpg|Olivine grains that eroded from [[lava]] on [[Papakolea Beach]], [[Hawaii]]
File:Peridot in basalt.jpg|Light green olivine crystals in peridotite xenoliths in basalt from Arizona
File:Lunar Olivine Basalt 15555 from Apollo 15 in National Museum of Natural History.jpg|Olivine [[basalt]] from the Moon, collected in 1971 by the crew of [[Apollo 15]]
File:Forsterite-158776.jpg|Bright green olivine from Pakistan, showing chisel termination and silky luster
File:Lava - Olivine - Azores.jpg|Olivine in lava from the [[Azores]]
</gallery>

===Extraterrestrial occurrences===
[[File:Météorite Esquel, exposition Météorites, Muséum national d'histoire naturelle de Paris 05.jpg|thumb|right|Crystals of olivine embedded in iron, in a slice of [[Esquel (meteorite)|Esquel]], a [[pallasite]] [[meteorite]]]]

Mg-rich olivine has also been discovered in [[meteorite]]s,<ref>[http://www.farlang.com/art/gemstone-meteorites Fukang and other Pallasites] {{webarchive|url=https://web.archive.org/web/20081221151620/http://www.farlang.com/art/gemstone-meteorites |date=2008-12-21}}. Farlang.com (2008-04-30). Retrieved on 2012-06-16.</ref> on the [[Moon]]<ref name="MareBasalt1">{{cite web | url=https://curator.jsc.nasa.gov/lunar/letss/mare3.pdf | title=Mare Basalt Volcanism | publisher=[[NASA]] | work=NASA Lunar Petrographic Educational Thin Section Set | date=2003 | access-date=23 October 2016 | author=Meyer, C. | url-status=live | archive-url=https://web.archive.org/web/20161221110429/https://curator.jsc.nasa.gov/lunar/letss/mare3.pdf | archive-date=21 December 2016}}</ref> and [[Mars]],<ref>[http://www.psrd.hawaii.edu/Nov03/olivine.html Pretty Green Mineral....] {{webarchive|url=https://web.archive.org/web/20070504025123/http://www.psrd.hawaii.edu/Nov03/olivine.html |date=2007-05-04}}[http://deepimpact.umd.edu/gallery/313_635_F3.html Mission Update 2006...] {{webarchive|url=https://web.archive.org/web/20100605183617/http://deepimpact.umd.edu/gallery/313_635_F3.html |date=2010-06-05}} UMD Deep Impact Website, University of Maryland Ball Aerospace & Technology Corp. retrieved June 1, 2010</ref><ref>Hoefen, T.M., et al. 2003. "Discovery of Olivine in the Nili Fossae Region of Mars". ''Science'' 302, 627–30. "{{cite journal |title=Discovery of Olivine in the Nili Fossae Region of Mars |journal=Science |volume=302 |issue=5645 |pages=627–630 |doi=10.1126/science.1089647 |year=2003 |last1=Hoefen |first1=T. M. |url=https://zenodo.org/record/1230836 |bibcode=2003Sci...302..627H |pmid=14576430|s2cid=20122017 }}"</ref> falling into infant stars,<ref>[http://www.nasa.gov/mission_pages/spitzer/news/spitzer20110526.html Spitzer Sees Crystal Rain...] {{webarchive|url=https://web.archive.org/web/20110529000009/http://www.nasa.gov/mission_pages/spitzer/news/spitzer20110526.html |date=2011-05-29}} NASA Website</ref> as well as on asteroid [[25143 Itokawa]].<ref>[http://www.spaceflightnow.com/news/n1011/16hayabusa/ Japan says Hayabusa brought back asteroid grains...] {{webarchive|url=https://web.archive.org/web/20101118234721/http://www.spaceflightnow.com/news/n1011/16hayabusa/ |date=2010-11-18}} retrieved November 18, 2010</ref> Such meteorites include [[chondrite]]s, collections of debris from the early [[Solar System]]; and [[pallasite]]s, mixes of iron-nickel and olivine. The rare [[A-type asteroid]]s are suspected to have a surface dominated by olivine.<ref>{{cite journal | title=Olivine-dominated asteroids: Mineralogy and origin | last1=Sanchez | first1=Juan A. | last2=Reddy | first2=Vishnu | last3=Kelley | first3=Michael S. | last4=Cloutis | first4=Edward A. | last5=Bottke | first5=William F. | last6=Nesvorný | first6=David | last7=Lucas | first7=Michael P. | last8=Hardersen | first8=Paul S. | last9=Gaffey | first9=Michael J. | last10=Abell | first10=Paul A. | last11=Le Corre | first11=Lucille | display-authors=1 | journal=Icarus | volume=228 | pages=288–300 | date=January 2014 | doi=10.1016/j.icarus.2013.10.006 | arxiv=1310.1080 | bibcode=2014Icar..228..288S | s2cid=42791787 }}</ref>

The [[spectral signature]] of olivine has been seen in the dust disks around young stars. The tails of comets (which formed from the dust disk around the young [[Sun]]) often have the spectral signature of olivine, and the presence of olivine was verified in samples of a comet from the [[Stardust (spacecraft)#Sample analysis|Stardust spacecraft]]{{Broken anchor|date=2024-06-25|bot=User:Cewbot/log/20201008/configuration|target_link=Stardust (spacecraft)#Sample analysis|reason= The anchor (Sample analysis) [[Special:Diff/413803820|has been deleted]].}} in 2006.<ref>[http://stardust.jpl.nasa.gov/news/status/060313.html Press Release 06-091] {{webarchive|url=https://web.archive.org/web/20060828230900/http://stardust.jpl.nasa.gov/news/status/060313.html |date=2006-08-28}}. Jet Propulsion Laboratory Stardust website, retrieved May 30, 2006.</ref> Comet-like (magnesium-rich) olivine has also been detected in the [[planetesimal]] belt around the star [[Beta Pictoris]].<ref name="deVries2012">{{Cite journal | last1=De Vries | first1=B. L. | last2=Acke | first2=B. | last3=Blommaert | first3=J. A. D. L. | last4=Waelkens | first4=C. | last5=Waters | first5=L. B. F. M. | last6=Vandenbussche | first6=B. | last7=Min | first7=M. | last8=Olofsson | first8=G. | last9=Dominik | first9=C. | last10=Decin | doi=10.1038/nature11469 | first10=L. | last11=Barlow | first11=M. J. | last12=Brandeker | first12=A. | last13=Di Francesco | first13=J. | last14=Glauser | first14=A. M. | last15=Greaves | first15=J. | last16=Harvey | first16=P. M. | last17=Holland | first17=W. S. | last18=Ivison | first18=R. J. | last19=Liseau | first19=R. | last20=Pantin | first20=E. E. | last21=Pilbratt | first21=G. L. | last22=Royer | first22=P. | last23=Sibthorpe | first23=B. | title=Comet-like mineralogy of olivine crystals in an extrasolar proto-Kuiper belt | journal=Nature | volume=490 | issue=7418 | pages=74–76 | year=2012 | pmid=23038467 | arxiv=1211.2626 | bibcode=2012Natur.490...74D| s2cid=205230613 }}</ref>