One of the reasons for selecting Meridiani Planum as one of the two landing sites for the MER (Mars Exploration Rover) mission was the detection of a hematite signature by the TES (Thermal Emission Spectrometer) instrument onboard MGS (Mars Global surveyor) . The presence of hematite at Meridiani has since been confirmed by instruments of the Athena Science Payload of the Opportunity MER rover [2,3]. Meridiani plains appear to be sulphur-rich sedimentary layered rocks covered by basaltic soils (outcrops being exposed within impact craters) [3,4]. Ubiquitous mm-sized spherules, nicknamed 'blueberries', have been observed in both the rocks and the soils. Opportunity's mini-TES and Mössbauer spectrometer (MB) have shown that hematite is present both in the matrix of the layered rocks and in the spherules [2,3].