keatite

{{Short description|Tetragonal polymorph of silica, mineral}}

{{Infobox mineral

| name = Keatite

| category = Tectosilicates, quartz group

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| image = Keatite.svg

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| caption = Crystal structure

| formula = SiO₂

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| habit = Microscopic inclusions

| strunz = 4.DA.45

| system = Tetragonal

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Keatite is a silicate mineral with the chemical formula SiO₂ (silicon dioxide) that was discovered in nature in 2013. It is a tetragonal polymorph of silica first known as a synthetic phase.[http://www.mindat.org/min-2173.html Ralph, Jolyon, and Ida Ralph. "Keatite: Keatite Mineral Information and Data." MinDat. 2013. Aug. 2013] It was reported as minute inclusions within clinopyroxene (diopside) crystals in an ultra high pressure garnet pyroxenite body. The host rock is part of the Kokchetav Massif in Kazakhstan.[http://www.minsocam.org/msa/ammin/toc/Abstracts/2013_Abstracts/Jan13_Abstracts/Hill_p187_13.pdf Abstract Hill, Tina R., Hiromi Konishi, and Huifang Xu, Natural occurrence of keatite precipitates in UHP clinopyroxene from the Kokchetav Massif: A TEM investigation, American Mineralogist, Volume 98, pages 187–196, 2013 ]

Keatite was synthesized in 1954 and named for Paul P. Keat who discovered it while studying the role of soda in the crystallization of amorphous silica.[https://www.science.org/doi/10.1126/science.120.3113.328 Science 120 (27 Aug1954) pp 328-330 with the title "A new crystalline silica.] Keatite was well known before 1970 as evidenced in few studies from that era.{{Cite journal|url=http://scripts.iucr.org/cgi-bin/paper?a08203|doi = 10.1107/S0567740871003649|title = Transformation mechanism between high-quartz and keatite phases of LiAlSi2O6 composition|year = 1971|last1 = Li|first1 = C. T.|journal = Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry|volume = 27|issue = 6|pages = 1132–1140}}{{Cite journal|url=http://eurjmin.geoscienceworld.org/content/7/6/1389|title=Keatite; II, Hydrothermal synthesis from silica-glass|journal=European Journal of Mineralogy|date=December 1995|volume=7|issue=6|pages=1389–1397|last1=Martin|first1=Brigitte|doi=10.1127/ejm/7/6/1389|bibcode=1995EJMin...7.1389M}}