During the study of some decay processes in marble covering the façade of the Florence Cathedral (1870-1887), vaterite was found as the principal component of some bonding mortars of inlay decorations.
Vaterite is one of the three polymorphous phases of CaCO3 and crystallizes in the hexagonal system, dihexagonal bipyramidal class (Kamhi, 1963; Sato and Matsuda, 1969): it is unstable under normal environmental conditions (Deer et al., 1964).