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A Roman “hologram” effect ring found in the grave of 1st century AD noblewoman, Aebutia Quarta.
(lemmy.world)
The ring is thought to depict her son, Titus Carvilius Gemello, who passed away at age of 18. Found at the Grottaferrata necropolis close to Rome.
My guess would be a painting under the rounded glass piece to make the painting move slightly through the curvature of the glass. But I’m just some guy.