Scientists have found a new organic molecule that may be the mysterious culprit that is turning some ancient stone tools blue and casting a blue sheen over other irreplaceable archaeological artifacts in an old armory in Verona, Italy.
Mineralogist Gilberto Artioli of the University of Padua in Italy told Science today that he has identified a new organic molecule that reacts with the minerals in the stone to turn them blue. He was asked this spring to analyze the stone tools by archaeologist Laura Longo, the former curator of Verona's Natural History Museum who was suspended without salary from her post this summer after she complained that the artifacts were damaged because they were stored improperly in a former military armory near Verona. The tools were moved out of the museum a few years ago when Verona's town council sold their original home in an 18th century castle to raise funds.
Artioli's preliminary analysis found that the stone artifacts were contaminated by hydrocarbons, but at first he couldn't identify the key pollutant. After analyzing more specimens for the regional ministry of culture in the Veneto region, he and chemist Andrea Tapparo of the University of Padua identified the culprit as a new molecule belonging to a known class of pigments. Still unnamed, the molecule apparently catalyzes a chemical reaction that turns the stone blue, says Artioli.
The regional culture ministry has put Artioli's chemical sensors in the armory to see if they can detect hydrocarbons. (The Italian press reported this week that the Italian army confirmed the presence of an underground oil tank inside the armory, which may be the source of the pollutants.)
Meanwhile, 42 eminent archaeologists and paleoanthropologists from the United States and Europe signed a letter demanding that Italy's minister of the cultural heritage move the archaeological collection to a new location and create an international scientific panel to assess the effects of the contamination. The collection includes stone tools and other artifacts, as well as fossilized bones of animals and ancient hominins, including the Neandertal bones that formed part of the sample used in three recent studies of Neandertal DNA. However, the hominin bones have been stored in a safe in the armory and so far show no visible damage, says paleoanthropologist Lorenzo Rook of the University of Florence in Italy, who delivered the letter to the Italian ministry last Friday. "The severe contamination of archaeological material has no precedent in the history of cultural heritage and caused irreversible alteration to the archaeological materials with enormous loss of scientific information," the scientists wrote.
*This item has been corrected. It now reflects that Laura Longo, the former curator of Verona's Natural History Museum, was suspended without salary from her post this summer; she was not dismissed. Additionally, the Neandertal bones in this collection were used in three recent studies of Neandertal DNA, and not in the Neandertal genome project.