Wairakite

{{Short description|Zeolite mineral}}

{{Infobox mineral

| name = Wairakite

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| image = Wairakite.jpg

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| caption = Wairakite from Azerbaijan

| category = Tectosilicate minerals, zeolite group

| formula = Ca₈(Al₁₆Si₃₂O₉₆)•16H₂O

| IMAsymbol = Wrk{{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}}

| molweight =

| strunz = 9.GB.05

| system = Monoclinic

| class = Prismatic (2/m)
(same H-M symbol)

| symmetry = I2/a

| unit cell = a = 13.69 Å, b = 13.64 Å
c = 13.56 Å; β = 90.51°; Z = 8

| color = colorless to white

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| luster = vitreous, dull

| streak = white

| diaphaneity = transparent, translucent

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| references = [http://www.mindat.org/min-4230.html Mindat][https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Wairakite Mineralienatlas]

}}

Wairakite is a zeolite mineral with an analcime structure but containing a calcium ion. The chemical composition is Ca₈(Al₁₆Si₃₂O₉₆)•16H₂O. It is named for the location of its discovery in Wairakei, North Island, New Zealand, by Czechoslovakian mineralogist Alfred Steiner in 1955.{{citation | first=Rosemarie | last=Szostak | year=1992 | title=Handbook of molecular sieves | page=482 | publisher=Springer | isbn=0-442-31899-5 | url=https://books.google.com/books?id=tSXDrpyqQc8C&pg=PA482 }}{{citation | last=Steiner | first=Alfred | year=1955 | title=Wairakite, the calcium analogue of analcime, a new zeolite mineral | journal= Mineralogical Magazine and Journal of the Mineralogical Society| volume=30 | issue=230 | pages=691–698 | doi=10.1180/minmag.1955.030.230.02 | bibcode=1955MinM...30..691S | url=http://rruff.info/uploads/MM30_691.pdf | accessdate=2011-09-08 }} The first finds were in hydrothermally altered rhyolitic tuffs, ignimbrites and volcaniclastic rocks. The mineral has since been found in metamorphic rocks and in geothermal areas. It was most likely first successfully synthesized in a laboratory in 1970.{{citation|authorlink1=Juhn G. Liou | first=J. G. | last=Liou | title=Synthesis and stability relations of wairakite, CaAl2 Si4 O12·2H2O | journal=Contributions to Mineralogy and Petrology | year=1970 | volume=27 | issue=4 | pages=259–282 | doi=10.1007/BF00389814 |bibcode = 1970CoMP...27..259L | s2cid=128557961 }}