More than 1,600 years after Roman artisans crafted the famous Lycurgus Cup, a University of Sheffield technical specialist has successfully replicated its color-shifting dichroic glass in quantity for the first time.
The ancient artifact, dating back to the 4th century, has long puzzled historians and glassmakers because its glass body transforms from jade green in reflected light to a striking ruby red when light passes through it. In 2022, an international panel of conservators and artists recognized the original vessel as one of the seven glass wonders of the world, honoring its unusual colors, exceptional preservation, and intricate artistry.
For decades, scholars understood that the optical phenomenon resulted from minuscule amounts of gold and silver embedded within the material. Research conducted during the mid-20th century indicated that these metals form layered nanoparticles smaller than the wavelengths of visible light.
Because these particles are smaller than a grain of sand, they absorb light strongly and block specific wavelengths depending on their size, shape, and composition, allowing red and orange to pass while shifting appearance based on the viewing angle.
Establishing a consistent and repeatable recipe had eluded modern experts. The breakthrough occurred after Christina Metcalfe, project manager for the Molecular Photonic Breadboards project, challenged University of Sheffield glass technician Lisa Hollands to replicate the material for a 2025 event called LightFest.
Hollands, who has studied and worked with glass for over 25 years, noted that the process required more than simply mixing off-the-shelf nanoparticles into molten material.
Partnering with leading Roman glass expert Professor Caroline Jackson, Hollands researched historical glass properties and utilized a gas-fired furnace—which produced much better results than electrically heated alternatives—to simulate the raw materials available to 4th-century artisans. The resulting formulation successfully self-strikes, yielding consistent, repeatable dichroic glass.
Following the successful replication of the glass, the team commissioned a contemporary sculpture to showcase its chameleon characteristics.
They partnered with British glass artist Elliot Walker, winner of season two of Netflix’s glass art series Blown Away,
who crafted a piece paying homage to the ancient twin. Walker’s sculpture draws inspiration from the tale of King Lycurgus depicted on the original artefact, substituting a cup into the design.
The completed sculpture made its debut at the University of Sheffield’s Festival of the Mind, held from November 6 to 15, 2026, following an initial sample display at Sheffield’s LightFest organized by the Molecular Photonic Breadboards project in partnership with the Universities of Sheffield and Bristol, with funding from the Engineering and Physical Sciences Research Council.
Following the festival, the sculpture will join the permanent collection at the university’s Turner Museum of Glass within the School of Chemical, Materials and Biological Engineering.
Hollands works within the Immobilisation Science Laboratory in the School of Chemical, Materials and Biological Engineering, where her daily research focuses on immobilizing complex nuclear wastes in glass to safely contain hazardous materials. Understanding how crystals form in these glass wasteforms helps maximize the amount of waste that can be safely stored. The project aims to support United Kingdom industries including solar energy, quantum technologies, and healthcare diagnostics.
by priyanka.patel tech editor