The Litho-Mineralogical collections comprise around 55,000 rock and mineral finds acquired since the late 19th century that document Italy’s lithological and mineralogical variety and repercussions on economic and infrastructure development, as well as artistic practices. Mineralogical specimens are grouped in different typological areas and arranged by systematic criteria. Some 46,000 examples come from the geological survey activities conducted on Italian territory from 1873 until the 1970s as the documentary basis indispensable in creating the Geological Map of Italy. The Regional Collections of building and decorative materials illustrate the variety of rocks and minerals in use when the Kingdom of Italy was established, whereas the Collection of Mineral Deposits (698 finds) consists of minerals of industrial interest including specimens of combustible fossils, oils, tars, and asphalts.

Among the Building and Decoration Material Collections, the ancient marbles in the Pescetto and De Santis Collections – on which the presentation in the Hall of Sciences is focused and for which new wall lithotheques and metal grids displays have been designed – vaunt special importance. These two collections offer lithotypes that were taken from quarries opened during the Roman empire and others located in Asia Minor and the Mediterranean basin and were also widely used by the ancient Egyptians and Greeks, as well as to adorn churches and monuments in medieval and modern Europe in later centuries. Established sometime around 1870 by Federico Pescetto, Senator of the Kingdom of Italy and General of the Corps of Engineers, the Pescetto Collection was first exhibited at the opening of the Agricultural Geological Museum in 1885 and purchased for the sum of 16,000 Liras. The Collection begun by Pio De Santis was instead acquired by the Monte di Pietà bank of Rome in 1878 for around 3,000 Liras. The two collections together comprise 1,358 specimens ordered by the classes that marble workers defined in the second half of the 19th century: Hard and semiprecious stones; Porphyries and basalts; Granites; Serpentines; Marbles in strict sense; Fossil Limestone; Breccias; and Alabasters. Hard or semi-precious stones are lithotypes of different petrographic origin characterized by their rarity, preciousness, and beauty: minerals such as malachite, fluorite, lazurite and silicon dioxide in all its forms, such as agate, jasper and amethyst, or rocks such as labradorite. Whether of primary or secondary igneous or chemical origin, they were already widely used in Antiquity for the decoration of public, religious, funerary, and statuary constructions and also in the fabrication of artistic objects, pottery, jewelry, and, in some cases, as pigment. The specimens of petrified wood—some of which taken from the ancient city of Nineveh in Mesopotamia (modern Iraq) — are also included in this class.