Parabutlerite Locality: Kavir-e-Sagand, Saghand (Sagand; Saqand), Yazd Province , Iran ( Locality at mindat.org ) Orange xls of Parabutlerite. Field of view 10 mm. Depth of field is achieved with CombineZM. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Parabutlerite
Parabutlerite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Fe³⁺(SO₄)(OH)·2H₂O.
It crystallizes in the orthorhombic crystal system (space group Pmnb).
Key properties: Mohs hardness 2.5; specific gravity 2.55; Vitreous luster; optically biaxial.
IMA symbol Pbtl, grandfathered status — known before the IMA’s founding, named in 1938.
Occurs as an uncommon mineral in the oxidized zone of pyritic veins, may be produced through alteration of other sulfates.
It is found associated with Copiapite, cuprocopiapite, butlerite, jarosite, melanterite, fibroferrite.
Its name comes from the Greek para, for near, and its relation to butlerite.