Technician Recreates Roman Cup’s Color-shifting Glass Effect

WHO:

Ars Technica - University of Sheffield researchers figured out how to recreate the glass recipe.

Phys.org - A technician replicated the color-changing effect of the Lycurgus Cup.

Phys.org - The British Museum houses the Lycurgus Cup.

WHAT:

Ars Technica - Researchers recreated the recipe for the Lycurgus Cup’s glass and its unusual optical effects.

Phys.org - The Lycurgus Cup is a world-renowned Roman glass artifact with a color-changing effect.

Phys.org - The cup’s dichroic glass appears jade green in reflected light and ruby red in transmitted light.

WHERE:

Phys.org - The Lycurgus Cup is housed in the British Museum.

WHEN:

Ars Technica - The cup is described as 1,600 years old.

Phys.org - The Lycurgus Cup dates to the 4th century A.D.

WHY:

Phys.org - The cup appears in contrasting colors depending on the position of the light source.

HOW:

Ars Technica - University of Sheffield researchers recreated the glass recipe.

Phys.org - The cup’s dichroic glass changes its apparent color according to whether light is reflected from it or transmitted through it.

(UPDATED October 27, 2026 16:12 UTC)

Researchers at the University of Sheffield have recreated the glass recipe behind the Lycurgus Cup’s striking color-changing effect. Housed in the British Museum, the 1,600-year-old Roman artifact appears jade green in reflected light and ruby red when light passes through it. Its dichroic glass creates the contrasting colors depending on how the light interacts with the cup.