It comes as a surprise to most glass artists to learn that dichroic glass was produced by the Romans as far back as the 4th century AD. Don't believe it? Behold the Lycurgus cup:
Using colloidal gold and silver to achieve the color-shifting effect, the cup appears green under normal lighting where the light reflects off the surface. Place the cup in the dark and put a bright light in the cup and the glass appears red under the transmitted light.
So, the next time you hear someone explaining how dichroic glass was invented by NASA, roll your eyes, say "I don't think so" and point them to today's GlassFact :)
