Sheffield researchers replicate ancient colour‑changing glass of Lycurgus Cup
University of Sheffield technicians have reproduced the 1,600‑year‑old colour‑shift effect of the Lycurgus Cup, confirming a repeatable glass recipe. The Roman cup, dated to around 400 CE, changes from jade green in reflected light to ruby red in transmitted light because of gold and silver nanoparticles smaller than visible wavelengths. The team, prompted by project manager Christina Metcalfe for the university’s LightFest, says the new glass matches the original’s optical properties, offering a reliable method to study the ancient technique.
Key facts
- Christina Metcalfe, project manager, tasked the team with reproducing the effect for LightFest 2025.
- The Lycurgus Cup was named one of seven glass wonders by an international panel in 2022.
- Only about 40 glass cage cups survive from the period, and the Lycurgus Cup is among them.
- Nanoparticles are embedded within the glass matrix, unlike surface coatings on daguerreotypes.
- The researchers plan to unveil a modern sculpture that demonstrates the same colour‑changing effect.
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Why it matters
Provides a reproducible method to investigate ancient nanomaterial engineering.
What changed
First published from Ars Technica, Phys.org and The Times of India