These evaporitic deposits, dating back to the Messinian (about 5.5 million years ago), formed in a closed salt lake, where water concentrated salts and gypsum until they were deposited in thick layers. Since the 19th century, miners extracted blocks of “Grasta gypsum” through hand-dug tunnels, using the pure veins to produce high-quality plasters and mortars. Even today, the silvery and pearly reflections of the crystals emerge along the abandoned corridors, offering the few authorized explorers an almost unreal spectacle.
Recent geological studies have revealed that this gypsum contains small inclusions of fossil brine, useful for reconstructing the climate and composition of ancient waters — testimony to a micro-evaporitic ecosystem that remained sealed underground for millennia. Visiting them means glimpsing a forgotten chapter of Sicilian mining history and discovering how, even in the depths of the earth, nature can sculpt works of crystalline art.