Icosahedrite

{{Short description|Quasicrystalline mineral}} {{Infobox mineral | name = Icosahedrite | boxwidth = | boxbgcolor = | image = KhatyrkiteXRD.PNG | imagesize = | alt = | caption = X-ray diffraction pattern of the natural Al₆₃Cu₂₄Fe₁₃, icosahedrite. | category = Native element mineral | formula = Al₆₃Cu₂₄Fe₁₃ | IMAsymbol = Ihd<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> | strunz = | dana = | system = Quasicrystal | symmetry = Icosahedral <br/>H-M symbol: {{overline|5}} {{overline|3}}m <br/>Space group: Fm {{overline|3}} {{overline|5}}<ref name=Bindi/> | unit cell = | molweight = | color = Dark grey, black | colour = | habit = Subhedral to anhedral grains | twinning = | cleavage = | fracture = Irregular | tenacity = | mohs = | luster = Metallic | streak = Grey | diaphaneity = Opaque | gravity = | density = | polish = | opticalprop = Isotropic | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = <ref name=Mindat>[http://www.mindat.org/min-40647.html Mindat.org]</ref> }}

'''Icosahedrite''' is the first known naturally occurring quasicrystal phase. It has the composition Al₆₃Cu₂₄Fe₁₃ and is a mineral approved by the International Mineralogical Association in 2010.<ref name=Bindi>{{cite journal | last = Bindi | first = L. | author2 = Paul J. Steinhardt | author3 = Nan Yao | author4 = Peter J. Lu | title = Icosahedrite, Al₆₃Cu₂₄Fe₁₃, the first natural quasicrystal | journal = American Mineralogist | volume = 96 | issue = 5–6 | pages = 928–931 | year = 2011 | url = http://wwwphy.princeton.edu/~steinh/icosahedriteAmMin.pdf | doi = 10.2138/am.2011.3758 | bibcode = 2011AmMin..96..928B | s2cid = 101152220 | access-date = 2011-10-05 | archive-date = 2012-04-04 | archive-url = https://web.archive.org/web/20120404114035/http://wwwphy.princeton.edu/~steinh/icosahedriteAmMin.pdf | url-status = dead }}</ref><ref>Commission on New Minerals and Mineral Names, [http://pubsites.uws.edu.au/ima-cnmnc/newminerals2010.pdf Approved as new mineral] {{Webarchive|url=https://web.archive.org/web/20120320182918/http://pubsites.uws.edu.au/ima-cnmnc/newminerals2010.pdf |date=2012-03-20 }}</ref> Its discovery followed a 10-year-long systematic search by an international team of scientists led by Luca Bindi and Paul J. Steinhardt to find the first natural quasicrystal.<ref name=Bindi2011>{{Cite journal | doi = 10.1073/pnas.1111115109 | pmid = 22215583 | last = Bindi | first = Luca |author2=John M. Eiler |author3=Yunbin Guan |author4=Lincoln S. Hollister |author5=Glenn MacPherson |author6=Paul J. Steinhardt |author7=Nan Yao | title = Evidence for the extraterrestrial origin of a natural quasicrystal | journal = Proceedings of the National Academy of Sciences | volume = 109 | issue = 5 | pages = 1396–1401 | date = 2012-01-03 |bibcode = 2012PNAS..109.1396B |pmc=3277151| doi-access = free }}</ref>

It occurs as tiny grains in a small sample labelled "khatyrkite" (catalog number 46407/G, housed in The Museum of Natural History, University of Florence, Italy), collected from an outcrop of weathered serpentinite in the Khatyrka ultramafic zone of the Koryak-Kamchatka area, Koryak Mountains, Russia. The rock sample also contains spinel, diopside, forsterite, nepheline, sodalite, corundum, stishovite, khatyrkite, cupalite and an unnamed AlCuFe alloy. Evidence shows that the sample is actually extraterrestrial in origin, delivered to the Earth by a CV3 carbonaceous chondrite asteroid that dates back 4.5 Gya.<ref name=Steinhardt2012>{{Cite journal | doi = 10.1007/s12210-012-0203-3 | last = Paul J. | first = Steinhardt | title = Quasicrystals: a brief history of the impossible, paper presented at the conference "The Centennial of X-Ray Diffraction (1912–2012)", held at Accademia Nazionale dei Lincei in Roma on May 8 and 9, 2012. | journal = Rend. Fis. Acc. Lincei | access-date = 2012-09-22 | date = 2012-09-15 | url = http://www.physics.princeton.edu/~steinh/Steinhardt_Rendiconti%20Lincei%202012.pdf | volume = 24 | pages = 85–91 | s2cid = 6500074 | archive-date = 2013-10-14 | archive-url = https://web.archive.org/web/20131014143203/http://www.physics.princeton.edu/~steinh/Steinhardt_Rendiconti%20Lincei%202012.pdf | url-status = dead }}</ref><ref name=Bindi2011/> A geological expedition has identified the exact place of the original discovery and found more specimens of the meteorite.<ref>Nadia Drake, [http://www.sciencenews.org/view/feature/id/345849/description/Prospecting_for_Quasicrystals Prospecting for Quasicrystals], ''Science News'', Print edition: Nov. 3, 2012; Vol.182 #9 (p. 24)/ Web edition: October 19, 2012 </ref><ref>A second natural quasicrystal with a different (decagonal) structure has been identified in the samples, {{cite journal | doi = 10.1038/srep09111 | bibcode=2015NatSR...5.9111B | volume=5 | title=Natural quasicrystal with decagonal symmetry | year=2015 | journal=Scientific Reports | article-number=9111 | last1 = Bindi | first1 = Luca| doi-access=free | pmid=25765857 | pmc=4357871 }}</ref> The same Al-Cu-Fe quasicrystal phase had previously been created in the laboratory by Japanese experimental metallurgists in the late 1980s.<ref name=n-Pang>{{Cite journal | doi = 10.1143/JJAP.26.L1505 | issn = 0021-4922 | volume = 26 | issue = Part 2, No. 9 | pages = L1505–L1507 | last = Tsai | first = An-Pang |author2=Akihisa Inoue |author3=Tsuyoshi Masumoto | title = A Stable Quasicrystal in Al-Cu-Fe System | journal = Japanese Journal of Applied Physics | date = 1987-09-20 |bibcode = 1987JaJAP..26L1505T | s2cid = 98442801 }}</ref>

The concept of quasicrystals — along with the term — was first introduced in 1984 by Steinhardt and Dov Levine, both then at the University of Pennsylvania. The first synthetic quasicrystal, a combination of aluminium and manganese, was reported in 1984 by Israeli materials scientist Dan Shechtman and colleagues at the U.S. National Institute of Standards and Technology, a finding for which Shechtman won the 2011 Nobel Prize for Chemistry.<ref>[https://www.princeton.edu/news/2012/01/12/quasicrystal-extraterrestrial-origin-princeton-researchers-find Extra-terrestrial Origin]</ref><ref>[https://interestingengineering.com/scientists-discovered-impossible-crystal-meteorite "Impossible" crystal discovery]</ref>

==References== {{Reflist}}

Category:Native element minerals Category:Aluminium minerals Category:Copper minerals Category:Iron minerals Category:Geology of Russia Category:Quasicrystals