Researchers at the University of Sheffield have recreated the colour-changing effect of the Lycurgus Cup, a Roman vessel about 1,600 years old. The cup appears green when light reflects off its surface, but red when light shines through it.
Scientists believe the Romans achieved this by adding extremely small particles of gold and silver to the glass. These particles block blue and green light while allowing red and orange light to pass through. When light hits the surface instead, the particles scatter it, producing the green appearance.
Lisa Hollands, who led the research, worked with Roman glass expert Caroline Jackson to recreate a basic glass similar to the Roman material. Hollands then experimented with ingredients and heating conditions until she found a reliable method. Her recipe uses only raw materials that Roman glass makers could have obtained. Even small changes in the glass's position inside the furnace could affect its colour.
British artist Elliot Walker has used the glass to create a sculpture inspired by the Lycurgus story and a Roman sculpture of Atlas. In his version, Atlas holds a cup instead of a globe. The work will be shown at the University of Sheffield's Festival of the Mind before going on permanent display at the university's Turner Museum of Glass.
