Siderotil is an iron(II) sulfate hydrate mineral with formula: FeSO4·5H2O which forms by the dehydration of melanterite.
[2] Copper commonly occurs substituting for iron in the structure.
Its name derives from the Greek sideros (iron) and tilos (fiber) in reference to its iron content and typical fibrous form.
[2] However, the material at the Idrija location may not be siderotil, but the mineral has been authenticated from a wide variety of worldwide locations.
This article about a specific sulfate mineral is a stub.