A few years ago, Northern Italy faced a scientific and political disaster. Priceless and irreplaceable ancient artifacts started turning blue.
These artifacts included human bones and stone tools from Europe’s last known Neanderthals, an extinct species that pre-dates modern humans. The artifacts were originally stored in an 18th-century castle near Verona’s Natural History Museum. When local officials sold the castle, they moved the artifacts to a former military armory for storage.
Over the next several months, more than one hundred of these artifacts started turning blue. Bright blue. Scientists accused the politicians of crimes against cultural heritage, for storing the artifacts in a building that had not been adequately checked for chemical pollutants. But what caused the discoloration?
Italian authorities used an Agilent HPLC with a Q-TOF and photodiode array detector to get to the bottom of the mystery. By analyzing the artifacts, they discovered three previously unknown pigmentation molecules that they named “Romeo Blue,” “Juliet Blue” and “Flint Blue.”
(Verona was the setting for Shakespeare’s play “Romeo and Juliet.” The artifacts that turned blue included prehistoric flint tools.)
Even more important, the researcher also identified the culprit: synthetic rubber mats in the armory storage cabinets. As the artifacts sat on these rubber mats, they apparently absorbed a chemical additive that was in the mats. The additive in turn caused a chemical reaction within the silica pore surface of the artifacts themselves.
The rubber mats were removed immediately. But while the artifacts could be bleached, they had lost their value to paleontologists for chemical analysis.
On the plus side, these chemically altered artifacts might have compromised future analytical research if their new color had not given them away. The researchers recommended more exceptional care in the storage of cultural heritage materials. And the world now has three new shades of blue.
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