Akdalaite

{{Short description|Very rare mineral}}

{{Infobox mineral

| name = Akdalaite

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| formula = {{chem2|5Al2O3*H2O|auto=1}}

| IMAsymbol = Akd

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| color = White, pale greenish yellow in thin section

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| fracture = Irregular/uneven

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| mohs = 7–7.5

| luster = Vitreous

| streak = White

| diaphaneity = Translucent

| gravity = 3.68

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Akdalaite (IMA symbol: Akd{{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}}) is a very rare mineral found in Kazakhstan and has the formula {{chem2|5Al2O3*H2O|auto=1}}.A New Occurrence and New Data on Akdalaite, a Retrograde Mineral from UHP Whiteschist, Kokchetav Massif, Northern Kazakhstan, Shyh-Lung Hwang, Pouyan Shen, Hao-Tsu Chu, Tzen-Fu Yui, International Geology Review, 48, 8, 2006, 754-764, {{doi|10.2747/0020-6814.48.8.754}} It was formerly believed to be {{chem2|4Al2O3*H2O}}. It is therefore the same as tohdite an artificially produced phase. Studies on the crystal structure and spectra indicate that this is an aluminium oxide hydroxide.Ab-initio quantum mechanical study of akdalaite (5Al2O3· H2O): structure and vibrational spectrum, Demichelis, R.; Noel, Y.; Zicovich-Wilson, C. M.; Roetti, C.; Valenzano, L.; Dovesi, R., Journal of Physics: Conference Series, Volume 117, Issue 1, pp. 012013 (2008)., {{doi|10.1088/1742-6596/117/1/012013}}