Ancient artefacts from Romeo and Juliet's hometown turning blue

Mysterious bright blue pigments found in artefacts from the hometown of Shakespeare's star-crossed lovers Romeo and Juliet are disturbing experts on conservation of archaeological treasures around the world.

The three new-to-science pigments are the topic of an article on the solution of an archaeological 'whodunit'.

Chemical and Engineering News editor Carmen Drahl said the mystery began last year when prehistoric flint tools began showing signs of contamination — a bright blue tinge.

The tainted relics came from a museum in Verona, Italy, the setting for Shakeaspeare's great tragedy.

Archaeologists said they were puzzled, having never encountered such a color change before, especially one involving a hard stone like flint.

Scientists have identified the pigments responsible for the blue colour, and have named the pigments Romeo Blue, Juliet Blue and Flint Blue.

An ingredient in synthetic rubber mats that held the tools was suspected as the origin of the pigments.

Archaeologists said the incident has led to a new awareness among museum conservation experts about unexpected interactions occurring between ancient treasures and the environments in which they are stored.

The article appears in the current edition of Chemical and Engineering News.