A Martian analog sample was collected during a field campaign by the Ma_MISS team geologists last October 2021.

It was gathered in a 120 cm-depth excavated trench in the Capalbio area (Tuscany, Italy). This clay was formed by pedogenetic processes following the hydrothermal fluid circulation of the Capalbio-Monti Romani belt (Pleistocene).

Its precursor was a metasedimentary rock. The mineral assemblage of the sample is constituted of Mg/Fe smectite, kaolinite, illite, quartz, and minor calcite. This composition resembles the superficial mineralogy of the oxia Planum landing site.