Originally described as the Na- and Mg-free end-member, termed AHF, of the ralstonite - aluminum hydroxide fluoride hydrate - AHF isostructural solid-solution series. The correct name was 'UM1980-03-F:AlHO'.
Later recognised as being identical to the newly defined hydrokenoralstonite (= former ralstonite) (Atencio et al., 2017).

The original material constitutes up to 40 vol.% of pale pink to pale yellow and white hydrothermally altered rhyolites at Big Southern Butte, Idaho, USA. Associates with quartz, tridymite and sanidine; also with halite, albite and fluorite.

As octahedra, up to 10-15 microns in size, forming compact masses (of grains). Also as rosettes on halite.
Observed in many fumarolic deposits.

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Unique IdentifiersHide

Mindat ID:

29352 (as AHF)
3354 (as Hydrokenoralstonite)

Long-form identifier:

mindat:1:1:29352:7 (as AHF)
mindat:1:1:3354:7 (as Hydrokenoralstonite)

GUID
(UUID V4):

fed8efa5-1901-4893-aa40-8180cf81e7db (as AHF)
bca8305f-3591-4b32-b127-1639f9cabac6 (as Hydrokenoralstonite)

Internet Links for AHFHide

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References for AHFHide

Reference List:

Carobbi, G. and Cipriani, C. (1951) Richerche su alcuni prodotti delle fumarole vesuviane. Rend. Soc. Ital. Mineral. Petrol.: 7: 43-44.

Naboko, S.I. (1957) A case of gaseous fluorine metasomatism at an active volcano. Geochemistry: 452-455.

Birnie, R.W. and Hall, J.H. (1974) The geochemistry of El Misiti volcano, Peru fumaroles. Bulletin of Volcanology: 38: 1-15.

Naughton, J.J., Greenberg, V.A., and Goguel, R. (1976) Incrustations and fumarolic condensates at Kilauea volcano, Hawaii: field, drill hole and laboratory observations. Journal Volcanol. Geotherm. Res.: 1: 149-165.

Desborough, G.A. and Rostad, O. (1980) Hydrated aluminum hydroxy-fluoride, a ralstonite-like mineral at Big Southern Butte, Snake River Plain, Idaho. American Mineralogist: 65: 1057-1058.

Rosenberg, P.E. (1988) Aluminum fluoride hydrates, volcanogenic salts from Mount Erebus, Antarctica. American Mineralogist: 73: 855-860.

Papike, J.J., Keith, T.E.C., Spilde, M.N., Galbreath, K.C., Shearer, C.K., and Laul, J.C. (1991) Geochemistry and mineralogy of fumarolic deposits, Valley of Ten Thousand Smokes, Alaska bulk chemical and mineralogical evlution of dacite-rich protolith. American Mineralogist: 76: 1662-1673.

Serafimova, E.K. (1997) Fluorides deposited during post-eruptive activities on Kamchatka volcanoes. Volcanol. Seismol.: 18: 571-614.

Africano, F. and Bernard, A. (2000) Acid alteration in the fumarolic environment of Usu volcano, Hokkaido, Japan. Journal of Volcanology and Geothermal Research: 97: 475-495.

Rosenberg, P.E. (2006) Stability relations of aluminum hydroxy-fluoride hydrate, a ralstonite-like mineral, in the system AlF3-Al2O3-H2O-HF. Canadian Mineralogist: 44: 125-134.

Atencio, D., Andrade, M.B., Bastos Neto, A.C., and Pereira, V.P. (2017): Ralstonite renamed hydrokenoralstonite, coulsellite renamed fluornatrocoulsellite, and their incorporation into the pyrochlore supergroup. Can. Mineral. 55, 115-120.

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