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Formula: Fe(UO2)(SO4)2(H2O)5
Uranyl sulphate
Crystal System: Orthorhombic
Specific gravity: 3.31 measured, 3.274 calculated
Hardness: 2
Streak: White
Colour: Brownish yellow
Luminescence: No fluorescence under long or short wave UV
Solubility: Easily soluble in room-temperature water
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Rietveldite occurs in association with other post-mining supergene
uranyl sulphates and uranium-free sulphates
(Mindat).
Localities
There are three co-type localities, the Jáchymov ore district, Karlovy Vary Region, Czech Republic, the Willi Agatz mine, Dresden,
Saxony, Germany and the Giveway-Simplot mine, Red Canyon Mining District, San Juan County, Utah, USA.
At the Jáchymov ore district, Karlovy Vary Region, Czech Republic, In Jáchymov, Western Bohemia, Czech Republic, rietveldite
was identified on one historical museum specimen on the strongly altered gangue in
association with rozenite, shumwayite and an
as yet unnamed aluminium-uranyl sulphate.
The rietveldite occurs as microcrystalline powdery aggregates up to several millimeters in size consisting of irregular
prismatic crystals up to 60 μm. The individual crystals are transparent and brownish yellow, while powdery aggregates have a
yellowish beige colour
(AM 102.2530).
At the Willi Agatz mine, Dresden, Saxony, Germany, rietveldite is a weathering product of
uranium-bearing coal and pyrite and is associated
with halotrichite, krausite,
melanterite, native sulphur and
voltaite.
The crystals of rietveldite are acicular to ruler-shaped blades up to 0.5 mm in length, usually growing in radiating
aggregates and intimately intergrown with halotrichite
(AM 102.2530).
At the Giveway-Simplot mine, Red Canyon Mining District, San Juan County, Utah, USA, rietveldite formed underground as a
result of postmining oxidation in the humid underground environment of the
primary ore minerals, that were deposited as replacements of wood and other
organic material and as disseminations in the enclosing sandstone. The
rietveldite was found on bitumen in association with ferricopiapite,
gypsum, römerite and
shumwayite, and on pyrite-impregnated
sandstone in association with gypsum,
halotrichite and römerite.
The rietveldite occurs in subparallel to random intergrowths of elongated and flattened crystals up to 0.5 mm long
(AM 102.2530).
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