Site distribution of iron in staurolite

The Mössbauer spectrum of staurolite does not necessarily indicate that ferrous iron is distributed over both the tetrahedral Fe site and one or more of the octahedral sites, as previously thought. Two doublets are present in the spectrum, but their quadrupole spliting and isomer shift are more consistent with both being due to tetrahedrally coordinated ferrous iron. Smith's X-ray work has shown that cations in the Fe site actually assume several slightly different positions, and iron in each of these positions may give rise to a different Mössbauer doublet.