Scientists rediscover how to make ancient Roman colour-changing glass

Scientists from the University of Sheffield have successfully replicated the optical properties of the Lycurgus Cup, a 1,600-year-old Roman masterpiece that appears jade green under normal light but turns ruby red when backlit. The breakthrough involved embedding microscopic gold and silver nanoparticles into molten glass, which scatter and filter light wavelengths to create the colour-changing effect—a feat of ancient engineering that has baffled experts for centuries. The research, led by Dr. Lisa Hollands and Prof. Caroline Jackson, used an ancient Roman recipe and modern understanding of nanotechnology to recreate this optical wonder.