The Lycurgus Cup: Dichroic Marvel of Ancient Glass Artistry and Unintended Nanotechnology. #Ancient

The magnificent Lycurgus cup from the fourth century would be remarkable even without anything else because of the elaborate artistic glass cage that encircles it and portrays a scenario from King Lycurgus' mythology.
Beyond its outward beauty, however, the Lycurgus cup's fundamental composition is a true antique marvel that baffles modern scholars.
The dichroic glass of the cup appears green when lit from the front and red when lit from the back.
Very few other examples of this phenomenon from the era exist, and none of them have a color differential that is as noticeable, comprehensive, or vast.
This is because the method for producing that dichroic effect necessitates the careful and controlled manipulation of nanoparticles made of gold and silver.