Scientists recreate the colour-changing glass of Rome's Lycurgus Cup

University of Sheffield researchers have replicated the optical trick of the 1,600-year-old Lycurgus Cup in the British Museum, which looks jade green in normal light and ruby red when lit from behind. Using an ancient recipe derived from a fragment of Roman dichroic glass, they embedded gold and silver nanoparticles in molten glass. Technician Lisa Hollands called the result 'magic'.