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Akdalaite

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(Redirected from Tohdite)
Akdalaite
General
CategoryMineral
Formula
(repeating unit)
5Al2O3·H2O
IMA symbolAkd
Identification
ColorWhite, pale greenish yellow in thin section
FractureIrregular/uneven
Mohs scale hardness7–7.5
LusterVitreous
StreakWhite
DiaphaneityTranslucent
Specific gravity3.68

Akdalaite (IMA symbol: Akd[1]) is a very rare mineral found in Kazakhstan and has the formula 5Al2O3·H2O.[2] It was formerly believed to be 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.[3]

References

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  1. ^ Warr, L.N. (2021). "IMA-CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ 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
  3. ^ 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
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