The Basaltina is a molten rock, grey in colour, recognised and used since Roman times, and excavated in Bagnoregio (Viterbo), near the Bolsena Lake. With its compact and uniform structure, the Basaltina has the physical-mechanical characteristics of being frost-resistant and resistant to both compression and wear.

A stone with a porous groundmass, essentially uniformly iron-grey in colour, only occasionally streaked with obvious straight dark grey lines, millimetres thick and decimetres long. Frequently scattered in the groundmass are whitish millimetre-large crystals. Holes, usually millimetres and often elongated, give the material a well-defined grain.