New data are presented here that document the previously poorly known magnetic
characteristics of sedimentary greigite (Fe3S4). Several diagnostic magnetic properties can
be used in conjunction to rapidly screen sediments to detect the presence of greigite. Such
discriminants are necessary because greigite displays a similar (or higher) range of
coercivities compared to most ferrimagnetic minerals and the commonly used method of
alternating field demagnetization cannot be used to distinguish between palaeomagnetic …

Greigite (Fe3S4) is an authigenic ferrimagnetic mineral that grows as a precursor to pyrite
during early diagenetic sedimentary sulfate reduction. It can also grow at any time when
dissolved iron and sulfide are available during diagenesis. Greigite is important in
paleomagnetic, environmental, biological, biogeochemical, tectonic, and industrial
processes. Much recent progress has been made in understanding its magnetic properties.
Greigite is an inverse spinel and a collinear ferrimagnet with antiferromagnetic coupling …