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Formula: Fe2+(SO4).4H2O
Hydrated sulphate, rozenite group
Crystal System: Monoclinic
Specific gravity: 2.293 measured, 2.29 calculated
Hardness: 2 to 3
Streak: White
Colour: Colourless to white, pale green
Solubility: Soluble in water
Environments
Sedimentary environments
Hydrothermal environments
Rozenite is an uncommon secondary mineral, at or
below 21oC under low humidity, formed directly from copper-free
melanterite, which is itself an alteration product of
pyrite or marcasite. Rozenite
also occurs as a post-mining product, in lake-bed sediments and in coal seams. Associated minerals include
melanterite, epsomite,
jarosite, gypsum,
sulphur, pyrite,
marcasite and limonite
(HOM, Mindat).
Localities
At the Francon quarry, Montreal, Quebec, Canada, rozenite is relatively rare, and is found as white powdery
coatings and globules on oxidised marcasite and
pyrite; it is occasionally associated with
natrojarosite and rarely with
halotrichite
(Minrec 37.1.43).
At the Sydney coalfield, Cape Breton county, Nova Scotia, Canada, hydrated sulphates associated with the
decomposition of pyrite and
copper-iron sulphides occur in coal
in contact with the atmosphere. Melanterite, rozenite,
epsomite, pickeringite,
halotrichite,
aluminocopiapite and
sideronatrite were identified from coal seams and mines in the coalfield
(CM 16.17-22).
At the type locality, Ornak Mountain, Tatra County, Lesser Poland Voivodeship, Poland, rozenite was found as
efflorescences on weathered gneiss containing
pyrite, and in an old gallery of the "Staszic"
pyrite mine at Rudki, Poland, where air temperatures were close to
30oC. At both places it was probably formed by the dehydration of
melanterite
(AM 46.242).
At the Clear Creek claim, Goat Mountain, New Idria Mining District, San Benito county, California, USA,
white coatings of rare rozenite on cinnabar have been identified
(Minrec 36.4.355).
At the Dolliver state park, near Fort Dodge, Webster county, Iowa, USA, abundant sulphate efflorescences on
sandstone consist of
halotrichite, szomolnokite
and rozenite. Melanterite may occur in place of the lower
hydrate, rozenite, during times of high humidity
(CM 11.958-970).
At abandoned coal strip mines at Sandy Run, Brown township, Vinton county, Ohio, USA, samples of altered
pyrite were collected from an abandoned mine dump. The samples were encrusted
either with masses of pale green fibres, or with extremely fine white powder, or with a mixture of both. The fibrous
material is melanterite and the remaining material is a mixture of
melanterite, rozenite and
halotrichite. Whether
melanterite or rozenite is the stable phase at any place or time
depends on the temperature and humidity. At humidity above about 95% the
melanterite deliquesces and becomes liquid.
(AM 50.1457-1461).
At the North Mesa 5 Mine, North Mesa Mine group, Temple Mountain, San Rafael Mining District, Emery county, Utah, USA,
rozenite occurs in a silicified tree that has a rim of coal around it, associated with
orthominasragrite,
anorthominasragrite,
minasragrite, bobjonesite,
szomolnokite, sulphur,
kornelite, montroseite, and
ferricopiapite
(Minrec 35.4.344).
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