Just read this very interesting article – it’s about how ancient Roman glass makers ground up silver and gold to the size of 50 nano-meters in diameter (less than 1000th the size of a grain of table salt) to produce a goblet that appears green when lit from the front and red when lit from behind.

No word on which extraterrestrial race gave the Romans this technology. I’m sure the news will be appearing on a future Ancient Aliens episode. They just have to do more “research” to figure out the alien connection since humans just couldn’t do this sort of thing.