“…The natural cleavage plane of the fluorite structure {1 1 1} (Tasker, 1979), was previously studied by scanning probe microscopy during growth (Hillner et al, 1993;Guntram and Werner, 1997;Schick et al, 2004), dissolution (Hillner et al, 1993;Guntram and Werner, 1997;Cama et al, 2010) and heating (Engelhardt et al, 2000). The observed changes on the surface during those processes include the formation of steps 0.33 nm high, corresponding to one F-Ca-F layer, and facets along {1 1 0} leading to the formation of triangular pits, which is attributed to the three fold symmetry of the {1 1 1} planes.…”