The color blue has a long, elusive history often due to its rarity in nature and sometimes toxic qualities.Analyzing a stone from the Paleolithic site Mühlheim-Dietesheim in Germany, however, researchers identified the earliest known use of blue mineral pigment in Europe. The results of the study, published in the journal Antiquity, offer new insights into early prehistoric use of the color.As part of the study, experts examined traces of blue residue found by archaeologists on a roughly 13,000-year-old stone artifact. Through scientific analyses, the team determined that the residue is the blue mineral pigment azurite. Until now, this mineral pigment had not been detected in Europe’s Paleolithic art.Instead, scholars have long believed that Paleolithic art used primarily red and black pigments, as that is what has been found so far from this time. Experts speculated that it could have been to a lack of blue minerals, which are not as easy to find in nature as other colors, or simply due to a lack of aesthetic allure.“This challenges what we thought we knew about Paleolithic pigment use,” lead author of the study Izzy Wisher from Denmark’s Aarhus University told Phys.org.The stone on which the azurite traces were found is thought to have been a kind of palette for mixing the blue pigments, indicating a more sophisticated process. The discovery also suggests that, instead of being used for art, blue mineral pigments would have been implemented for such activities as bodily adornment or fabric dyeing that leave little to no archaeological trace.“The presence of azurite shows that Paleolithic people had a deep knowledge of mineral pigments and could access a much broader color palette than we previously thought—and they may have been selective in the way they used certain colors,” Wisher continued.