The importance of the magnetic iron sulfide minerals, greigite (Fe3S4) and pyrrhotite (Fe7S8), is often underappreciated in geochemical studies because they are metastable with respect to pyrite (FeS2). Based on magnetic properties and X-ray diffraction analysis, previous studies have reported widespread occurrences of these magnetic minerals along with magnetite (Fe3O4) in two thick Plio-Pleis...

Some bacteria form intracellular nanometer-scale crystals of greigite (Fe3S4) that cause the bacteria to be oriented in magnetic fields. Transmission electron microscope observations showed that ferrimagnetic greigite in these bacteria forms from nonmagnetic mackinawite (tetragonal FeS) and possibly from cubic FeS. These precursors apparently transform into greigite by rearrangement of iron ato...

Introduction: The compositions, textures, and crystal structures of sulfides can be used to constrain oxygen fugacity, aqueous, thermal, and cooling history [e.g., 1–5]. The most abundant sulfides in extraterrestrial samples are the pyrrhotite group [(Fe,Ni,Co,Cr)1– xS], which can occur with pentlandite [(Fe,Ni,Co,Cr)9– xS8]. The pyrrhotite group sulfides are largely nonstoichiometric and have ...

hired is a large gold prospecting area which is located in south khorasan province, in the east of iran. gold mineralization is found in 4 target areas covering about 24 km2. the host rocks are mainly tertiary volcanics, some jurassic and cretaceous sediments. sub-volcanic rocks are of magnetite series (gabbros to diorite) and ilmenite series (granite-granodiorite-monzonite) which have intruded...