Siderotil is an
iron(II) sulfate
Iron(II) sulfate (British English: iron(II) sulphate) or ferrous sulfate denotes a range of salts with the formula Fe SO4·''x''H2O. These compounds exist most commonly as the heptahydrate (''x'' = 7) but several values for x are know ...
hydrate mineral with formula: FeSO
4·5H
2O which forms by the dehydration of
melanterite
Melanterite is a mineral form of hydrous iron(II) sulfate: FeSO4·7H2O. It is the iron analogue of the copper sulfate chalcanthite. It alters to siderotil by loss of water. It is a secondary sulfate mineral which forms from the oxidation of prima ...
.
[Mindat.org]
/ref> Copper commonly occurs substituting for iron in the structure. It typically occurs as fibrous or powdery encrustations, but may also occur as acicular triclinic
180px, Triclinic (a ≠ b ≠ c and α ≠ β ≠ γ )
In crystallography, the triclinic (or anorthic) crystal system is one of the 7 crystal systems. A crystal system is described by three basis vectors. In the triclinic system, the crystal is ...
crystals.[
It was first described in 1891 for an occurrence in the Idrija Mine, ]Idrija
Idrija (, in older sources ''Zgornja Idrija''; german: (Ober)idria, it, Idria) is a town in western Slovenia. It is the seat of the Municipality of Idrija. It is located in the traditional region of Inner Carniola and is in the Gorizia Statisti ...
, Slovenia
Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...
. Its name derives from the Greek ''sideros'' (iron) and ''tilos'' (fiber) in reference to its iron content and typical fibrous form.[ However, the material at the Idrija location may not be siderotil, but the mineral has been authenticated from a wide variety of worldwide locations.][Handbook of Mineralogy]
/ref>
References
Sulfate minerals
Iron(II) minerals
Triclinic minerals
Minerals in space group 2
Chalcanthite group
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