In recent times the role of experts of the so-called hard sciences has become increasingly important for the study of Cultural Heritage materials. As it is well known, many of these consist of geomaterials, which is why geosciences, in their broadest sense, and mineralogy, petrography and geochemistry in a more specific way, can serve to explore issues related to provenance, technology, and conservation of architectural, archaeological, and fine arts items. In September 2018, the annual Italian Congress SGI-SIMP, organized by Società Geologica Italiana (SGI) and Società Italiana di Mineralogia e Petrologia (SIMP), with the support of the University of Catania in Italy, was entitled Geosciences for the environment, natural hazard and cultural heritage, also hosting the thematic session Geosciences for Cultural Heritage. This to underline that a proper investigation of natural and artificial materials (i.e., stones, ceramics/bricks, plasters, mortars, pigments, glasses, metals, etc.) of architectural, archaeological, and artistic heritage cannot exclude the support of geoscientists. The scientific program was focused on material characterization by using classical and innovative methods, application of non-destructive techniques, chemometrics for cultural heritage, and conservation of building stones. These topics were presented in one Invited Lecture, 21 oral communications and 25 poster contributions. The high quality of these studies was reflected in the 11 selected papers published in this Special Issue, whose most important outcomes are shown below.