The pitch stone is a soft limestone impregnated with proportions ranging from 4% to 10% bitumen, the mineral that has made Ragusa, for centuries was used by the Sicilian artisans like a stone cutting in addition to decorate, recover and pave the most prestigious aristocratic palaces, as well as churches and monuments.

This morphological origin makes it particularly unique for the chromatic variation that characterizes it, in fact the pitch stone, also called "rock asphaltic" can take various shades from brown to almost black, while the simultaneous presence of fossils and still grains of enhancing it