Iron-doped zirconium silicate .1. The location of iron

Iron-doped zirconium silicate (zircon) has been shown by X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDX) and Fe-57 Mossbauer spectroscopy to consist of inclusions of alpha-Fe2O3 together with discrete paramagnetic Fe3+ species within the zircon structure. Electron paramagnetic resonance(EPR) spectra show that the Fe3+ species in the samples containing less than 0.2 mass % Fe occupies low-symmetry rhombic sites, but that in materials with higher concentrations of iron the Fe3+ also occupies other locations, including sites with axial symmetry. The colour of the iron-doped zircon is due to both the low symmetry Fe3+ species and the inclusions of alpha-Fe2O3.