has the olivine structure Pnma with , and at room temperature. The Mössbauer spectrum at 295 K consists of two doublets having centroid shifts (relative to ) and quadrupole splittings for the two metal positions Fe1 (point symmetry ) and Fe2 (point symmetry m) of , and . A point charge calculation for the nearest S octahedra gives the Mössbauer asymmetry parameters and for Fe1 and Fe2 respectively, and for both positions. At approximately 130 K there is an antiferromagnetic transition, and a second transition to a ferromagnetic or ferrimagnetic structure takes place at approximately 30 K. Both magnetic regions show complicated Mössbauer spectra, which require the full Hamiltonian for their analysis. Comparisons are made with Mössbauer results on the related minerals (fayalite), (iron sarcopside), and .