Stumbled onto a very nice piece on the Smithsonian website today about the Lycurgus Cup, a famous artifact currently held by the British Museum. The cup is believed to have been manufactured in Late Antiquity, around the 4th century, by a highly accomplished craftsman working in dichroic glass.
The cup has properties that appear almost magical to the untrained eye, with a distinctly green color when viewed normally, and a brilliant red color when backlit. Analysis of the artifact reveals an early use of “nanotechnology”: the ancient craftsmen incorporated very tiny particles of gold and silver into the glass to achieve this effect.
As with many great artifacts from Late Antiquity, this one has a very dodgy provenance–it turns up around 1800, and is believed to have been looted from a Church treasury during the French Revolution and its attendant wars. It may have been hoarded and stored continuously above ground since it was made, or it may have been looted at some point from a sarcophagus–impossible to say.
What I can say is that Roman glassworking, particularly some of the mixed material glassworking of Late Antiquity, is a subject I find endlessly fascinating. I have been very interested in it since I saw the gold glass samples excavated from the Roman catacombs of the period.