In medieval Europe this (nowadays) semiprecious stone was the most expensive pigment available, valued more than gold. Two scenarios are most likely to explain how the rare pigment ended between the woman's teeth. Traces of pigment were transferred into the mouth, where they eventually were deposited in the forming dental plaque. It is also possible that the woman was preparing the pigment, crushing the mineral, and inhaled tiny traces of the blue powder. In any case, the woman was allowed direct access to the precious pigment, suggesting she was highly valued for her skills.

Source: Forbes January 12, 2019 19:18 UTC