The 1,600-year-old Lycurgus Cup artifact defies logic with its ability to change color. He could claim the title of "The Holy Grail". However, the history of the creation of the Lycurgus Cup goes back to the Roman Empire of the 4th century.
The chalice got its name from the relief image of the legendary legislator Lycurgus of Sparta, who ruled around 800 BC. It is a story in which Lycurgus is trapped in vines as punishment for his atrocities.
King of Thrace Lycurgus - opponent of the cult of Dionysus.
When light hits the goblet at a certain angle, the glass reflects it as green, and from another angle gives it a shade of red. The cup doesn't just change its appearance when exposed to light. Even different liquids affect the shade of the bowl - they change the interaction of vibrational electrons in the glass and therefore the color.
The effect could not be explained until the 1990s, because it was then that modern technology "caught up" with the Romans, those guys who went to war in sandals. They impregnated the glass with the smallest particles of silver and gold (less than one thousandth the size of a grain of table salt).
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The exact proportions of precious metals show that Roman artisans knew what they were doing.