Editing Aluminium (section)

==Natural occurrence==
{{See also|List of countries by bauxite production}}

=== Space ===

Aluminium's per-particle abundance in the [[Solar System]] is 3.15 [[parts per million|ppm]] (parts per million).<ref name="Lodders">{{cite journal
|last1=Lodders|first1=K.|author1-link=Katharina Lodders|title=Solar System abundances and condensation temperatures of the elements
|url=http://solarsystem.wustl.edu/wp-content/uploads/reprints/2003/Lodders%202003%20ApJ%20Elemental%20abundances.pdf|year=2003|pages=1220–1247
|journal=[[The Astrophysical Journal]]|volume=591|issue=2|issn=0004-637X|doi=10.1086/375492|bibcode=2003ApJ...591.1220L|s2cid=42498829 |access-date=15 June 2018
|archive-date=12 April 2019|archive-url=https://web.archive.org/web/20190412090136/http://solarsystem.wustl.edu/wp-content/uploads/reprints/2003/Lodders%202003%20ApJ%20Elemental%20abundances.pdf|url-status=live}}
</ref>{{efn|Abundances in the source are listed relative to silicon rather than in per-particle notation. The sum of all elements per 10<sup>6</sup> parts of silicon is 2.6682{{e|10}} parts; aluminium comprises 8.410{{e|4}} parts.}} It is the twelfth most abundant of all elements and third most abundant among the elements that have odd atomic numbers, after hydrogen and nitrogen.<ref name="Lodders" /> The only stable isotope of aluminium, <sup>27</sup>Al, is the eighteenth most abundant nucleus in the universe. It is created almost entirely after fusion of carbon in massive stars that will later become [[Type II supernova]]s: this fusion creates <sup>26</sup>Mg, which upon capturing free protons and neutrons, becomes aluminium. Some smaller quantities of <sup>27</sup>Al are created in [[hydrogen burning]] shells of evolved stars, where <sup>26</sup>Mg can capture free protons.<ref name="Clayton" /> Essentially all aluminium now in existence is <sup>27</sup>Al. <sup>26</sup>Al was present in the early Solar System with abundance of 0.005% relative to <sup>27</sup>Al but its half-life of 728,000 years is too short for any original nuclei to survive; <sup>26</sup>Al is therefore [[extinct radionuclide|extinct]].<ref name="Clayton">{{Cite book
|last=Clayton|first=D.|title=Handbook of Isotopes in the Cosmos : Hydrogen to Gallium.|date=2003
|url=https://www.worldcat.org/oclc/609856530
|publisher=Cambridge University Press|location=Leiden|pages=129–137|oclc=609856530|isbn=978-0-511-67305-4|access-date=13 September 2020
|archive-url=https://web.archive.org/web/20210611060733/https://www.worldcat.org/title/handbook-of-isotopes-in-the-cosmos-hydrogen-to-gallium/oclc/609856530|archive-date=11 June 2021|url-status=live}}</ref> Unlike for <sup>27</sup>Al, hydrogen burning is the primary source of <sup>26</sup>Al, with the nuclide emerging after a nucleus of <sup>25</sup>Mg catches a free proton. However, the [[trace radioisotope|trace quantities]] of <sup>26</sup>Al that do exist are the most common [[gamma ray]] emitter in the [[interstellar gas]];<ref name="Clayton" /> if the original <sup>26</sup>Al were still present, [[Gamma-ray astronomy|gamma ray maps]] of the Milky Way would be brighter.<ref name="Clayton" />

=== Earth ===

[[File:Bauxite hérault.JPG|thumb|[[Bauxite]], a major aluminium ore. The red-brown color is due to the presence of [[iron oxide]] minerals.]]
Overall, the Earth is about 1.59% aluminium by mass (seventh in abundance by mass).<ref name="mit1">William F McDonough [https://web.archive.org/web/20110928074153/http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf The composition of the Earth]. quake.mit.edu, archived by the Internet Archive Wayback Machine.</ref> Aluminium occurs in greater proportion in the Earth's crust than in the universe at large. This is because aluminium easily forms the oxide and becomes bound into rocks and stays in the [[Earth's crust]], while less reactive metals sink to the core.<ref name="Clayton" /> In the Earth's crust, aluminium is the most abundant metallic element (8.23% by mass<ref name="Cardarelli 2008 p158-163" />) and the third most abundant of all elements (after oxygen and silicon).{{sfn|Greenwood|Earnshaw|1997|pp=217–219}} A large number of silicates in the Earth's crust contain aluminium.<ref name="WadeBanister2016">{{cite book
|last1=Wade|first1=K.|last2=Banister|first2=A.J.|title=The Chemistry of Aluminium, Gallium, Indium and Thallium: Comprehensive Inorganic Chemistry
|url=https://books.google.com/books?id=QwNPDAAAQBAJ&pg=PA1049|year=2016
|publisher=Elsevier|isbn=978-1-4831-5322-3|page=1049|access-date=17 June 2018
|archive-date=30 November 2019|archive-url=https://web.archive.org/web/20191130020257/https://books.google.com/books?id=QwNPDAAAQBAJ&pg=PA1049|url-status=live}}</ref> In contrast, the Earth's [[mantle (geology)|mantle]] is only 2.38% aluminium by mass.<ref>{{cite book
|last1=Palme|first1=H.|last2=O'Neill|first2=Hugh St. C.|title=The Mantle and Core
|editor-last=Carlson|editor-first=Richard W.|year=2005|publisher=Elseiver
|chapter-url=https://www.geol.umd.edu/~mcdonoug/KITP%20Website%20for%20Bill/papers/Earth_Models/3.1%20Palme%20&%20O'Neill%20Primative%20mantle%20(1).pdf|page=14 |access-date=11 June 2021|chapter=Cosmochemical Estimates of Mantle Composition
|archive-date=3 April 2021|archive-url=https://web.archive.org/web/20210403101355/https://www.geol.umd.edu/~mcdonoug/KITP%20Website%20for%20Bill/papers/Earth_Models/3.1%20Palme%20%26%20O%27Neill%20Primative%20mantle%20%281%29.pdf|url-status=live}}</ref> Aluminium also occurs in seawater at a concentration of 0.41 μg/kg.<ref>{{cite journal | doi=10.3389/fmars.2020.00468 | doi-access=free | title=A First Global Oceanic Compilation of Observational Dissolved Aluminum Data with Regional Statistical Data Treatment | date=2020 | last1=Menzel Barraqueta | first1=Jan-Lukas | last2=Samanta | first2=Saumik | last3=Achterberg | first3=Eric P. | last4=Bowie | first4=Andrew R. | last5=Croot | first5=Peter | last6=Cloete | first6=Ryan | last7=De Jongh | first7=Tara | last8=Gelado-Caballero | first8=Maria D. | last9=Klar | first9=Jessica K. | last10=Middag | first10=Rob | last11=Loock | first11=Jean C. | last12=Remenyi | first12=Tomas A. | last13=Wenzel | first13=Bernhard | last14=Roychoudhury | first14=Alakendra N. | journal=Frontiers in Marine Science | volume=7 | page=468 | bibcode=2020FrMaS...7..468M | hdl=10553/74194 | hdl-access=free }}</ref>

Because of its strong affinity for oxygen, aluminium is almost never found in the elemental state; instead it is found in oxides or silicates. [[Feldspar]]s, the most common group of minerals in the Earth's crust, are aluminosilicates. Aluminium also occurs in the minerals [[beryl]], [[cryolite]], [[garnet]], [[spinel]], and [[turquoise]].<ref>{{Cite book|url=https://books.google.com/books?id=v-04Kn758yIC&pg=PA17|title=Chemistry of Aluminium, Gallium, Indium and Thallium|last=Downs|first=A.J.|date=1993|publisher=Springer Science & Business Media|isbn=978-0-7514-0103-5|language=en|access-date=14 June 2017|archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725044500/https://books.google.com/books?id=v-04Kn758yIC&pg=PA17|url-status=live}}</ref> Impurities in Al<sub>2</sub>O<sub>3</sub>, such as [[chromium]] and [[iron]], yield the [[gemstone]]s [[ruby]] and [[sapphire]], respectively.<ref name="KotzTreichel2012">{{cite book|url=https://books.google.com/books?id=eUwJAAAAQBAJ&pg=PA300|title=Chemistry and Chemical Reactivity|last1=Kotz|first1=John C.|last2=Treichel|first2=Paul M.|last3=Townsend|first3=John|publisher=Cengage Learning|year=2012|isbn=978-1-133-42007-1|page=300|access-date=17 June 2018|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222050939/https://books.google.com/books?id=eUwJAAAAQBAJ&pg=PA300|url-status=live}}</ref> [[Native aluminium]] metal is extremely rare and can only be found as a minor phase in low oxygen [[fugacity]] environments, such as the interiors of certain volcanoes.<ref>{{cite web|url=http://webmineral.com/data/Aluminum.shtml|title=Aluminum Mineral Data|last1=Barthelmy|first1=D.|website=Mineralogy Database|archive-url=https://web.archive.org/web/20080704001129/http://webmineral.com/data/Aluminum.shtml|archive-date=4 July 2008|url-status=live|access-date=9 July 2008}}</ref> Native aluminium has been reported in [[cold seep]]s in the northeastern [[continental slope]] of the [[South China Sea]]. It is possible that these deposits resulted from [[bacteria]]l [[Redox|reduction]] of tetrahydroxoaluminate Al(OH)<sub>4</sub><sup>−</sup>.<ref name="Chen 2011">{{cite journal|last1=Chen|first1=Z.|last2=Huang|first2=Chi-Yue|last3=Zhao|first3=Meixun|last4=Yan|first4=Wen|last5=Chien|first5=Chih-Wei|last6=Chen|first6=Muhong|last7=Yang|first7=Huaping|last8=Machiyama|first8=Hideaki|last9=Lin|first9=Saulwood|date=2011|title=Characteristics and possible origin of native aluminum in cold seep sediments from the northeastern South China Sea|journal=Journal of Asian Earth Sciences|volume=40|issue=1|pages=363–370|bibcode=2011JAESc..40..363C|doi=10.1016/j.jseaes.2010.06.006}}</ref>

Although aluminium is a common and widespread element, not all aluminium minerals are economically viable sources of the metal. Almost all metallic aluminium is produced from the [[ore]] [[bauxite]] (AlO<sub>''x''</sub>(OH)<sub>3–2''x''</sub>). Bauxite occurs as a [[weathering]] product of low iron and silica bedrock in tropical climatic conditions.<ref>{{cite book|title=The Geology of Ore Deposits|last1=Guilbert|first1=J.F.|last2=Park|first2=C.F.|date=1986|publisher=W.H. Freeman|isbn=978-0-7167-1456-9|pages=774–795}}</ref> In 2017, most bauxite was mined in [[Australia]], [[China]], [[Guinea]], and [[India]].<ref>{{cite web |author=United States Geological Survey |title=Bauxite and alumina |year=2018 |url=https://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2018-bauxi.pdf |access-date=17 June 2018 |series=Mineral Commodities Summaries |archive-date=11 March 2018 |archive-url=https://web.archive.org/web/20180311202117/https://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2018-bauxi.pdf |url-status=live }}</ref>