Researchers recreate consistent Roman glass recipe behind the Lycurgus Cup

Researchers at the University of Sheffield have devised a consistent, replicable recipe for dichroic glass, which exhibits optical changes depending on light orientation, according to Ars Technica, ARTnews.com, and GreekReporter.com. Scientists Lisa Hollands and Caroline Jackson, who is an expert on Roman glass, developed the method to recreate the color-shifting properties of the 1,600-year-old Roman artifact known as the Lycurgus Cup. [1][3][4]

Dichroic glass presents different colors based on how light travels through it, appearing red when illuminated from behind and green when illuminated from the front. The Lycurgus Cup is a 4th-century Roman cage cup and remains the only complete ancient glass object made from this specific type of material. [5]

In 2020, Dutch researchers reproduced the green and red dichroic effect using a 3D-printable nanocomposite material that contained silver and gold nanoparticles, Ars Technica reported. However, that study did not establish a consistent recipe for standard glass production. To achieve a reliable formulation, Hollands and Jackson experimented with various furnace types, input materials, oxygen levels, and sugar additives. [1]

Hollands explained that creating dichroic glass required more complex methods than simply placing nanoparticles into a base mixture, Ars Technica reported. The process required exact control of heating environments and chemical additives to duplicate the historical nano-scale optical properties. [1]