Mohrite, (NH<sub>4</sub>)<sub>2</sub>Fe(SO<sub>4</sub>)<sub>2</sub>÷6 H<sub>2</sub>O, is a rare ammonium iron(II) sulfate mineral originally found in the geothermal fields of Tuscany, Italy. This Fe-dominant analogue of boussingaultite is sometimes reported from burning coal dumps where it is a product of pyrite oxidation.
The mineral crystallizes in the monoclinic crystal system with space group P2<sub>1</sub>/a.