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Formula: (H3O)Fe3+3(SO4)2(OH)6
Sulphate, alunite group,
alunite supergroup,
hydronium mineral
Crystal System: Trigonal
Specific gravity: 2.9 to 3.26 measured, 3.01 calculated
Hardness: 4 to 4½
Streak: Pale yellow
Colour: Amber-yellow to dark brown
Solubility: Insoluble in water, soluble in hydrochloric acid
Environments
Hydroniumjarosite occurs in the oxidised zone of rapidly weathering sulphide-bearing rocks; it may be of
post-mining formation. It is relatively uncommon because the ubiquitous abundance of alkali ions in surface waters
normally precludes its stability. Melanterite and
goethite are common associates
(HOM).
Most jarosites occurring in nature will probably contain a combination of potassium, sodium and hydronium in
the A-position. Hydroniumjarosite is rare and exists only in areas where iron-bearing sulphate solutions have
a deficiency of alkali due to rapid oxidation of pyrite accompanied
by rapid neutralisation of the solution such as by carbonate rocks to
precipitate the jarosite before the alkali in the country rock can be dissolved
(AM 50.1595-1607).
Localities
At Cerros Pintados, Tamarugal Province, Tarapacá, Chile, natural hydroniumjarosite has been found
(MM 78.535–547).
Hydroniumjarosite from Chile
There are two co-type localities, the Thorez mine, Śródmieście, Wałbrzych, Lower Silesian Voivodeship, Poland and
the Staszic Mine, Rudki, Nowa Słupia, Kielce County, Świętokrzyskie Voivodeship, Poland.
At the Staszic Mine, Rudki, Nowa Słupia, Kielce County, Świętokrzyskie Voivodeship, Poland, hydroniumjarosite
occurs as crusts deposited on a dolomitic zone in the mine, formed
after a gallerly had been opened. At the Thorez coal mine jarosite with a low alkali content was found in a
gallery where the temperature was 32oC. The jarosite occurs in the coal bed
shale along with
melanterite and goethite. The
low alkaii content in the mine waters, due to the more rapid decay of the sulphides rather than the rock-forming
minerals gives rise to the hydroniumjarosite
(AM 50.1595-1607).
Hydroniumjarosite from Poland -
Image
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