Bituminous rock or “Pietra Pece” is a limestone impregnated with bitumen, i.e. petroleum.
The first evidence of pietra pece stone working in Ragusa dates back to Greek times.
In fact, some sarcophagi were found in the southern outskirts of the town.
Other ancient artefacts date from all ages such as the capitals of the two cathedrals of San Giorgio (St. George) and San Giovanni (St. John).
Other evidence of pietra pece working can be found in the travel diaries of Frenchman Jean Houël at the beginning of the 19th century, and his compatriot, geologist Déodat de Dolomieu a few years later.
