AHF
A synonym of Hydrokenoralstonite
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Formula:
Al16(F,OH)48 · 12-15H2O
Crystal System:
Isometric
Name:
From the chemical components.
Synonym:
A synonym of Hydrokenoralstonite
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.
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.
Unique Identifiers
Mindat ID:
29352 (as AHF)
3354 (as Hydrokenoralstonite)
3354 (as Hydrokenoralstonite)
Long-form identifier:
mindat:1:1:29352:7 (as AHF)
mindat:1:1:3354:7 (as Hydrokenoralstonite)
mindat:1:1:3354:7 (as Hydrokenoralstonite)
Internet Links for AHF
mindat.org URL:
https://www.mindat.org/min-29352.html
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References for AHF
Reference List:
Naughton, J.J.; Greenberg, V.A.; Goguel, R. (1976) Incrustations and fumarolic condensates at Kilauea volcano, Hawaii: field, drill-hole and laboratory observations. Journal of Volcanology and Geothermal Research, 1 (2). 149-165 doi:10.1016/0377-0273(76)90004-4
Desborough, George A., Rostad, Ora (1980) Hydrated aluminum hydroxy-fluoride, a ralstonite-like mineral at Big Southern Butte, Snake River Plain, Idaho. American Mineralogist, 65 (9-10) 1057-1058
Africano, F, Bernard, A (2000) Acid alteration in the fumarolic environment of Usu volcano, Hokkaido, Japan. Journal of Volcanology and Geothermal Research, 97 (1) 475-495 doi:10.1016/s0377-0273(99)00162-6
