To make the cup, they would have had to grind up gold and silver into grains many times smaller than sand and fuse it to the glass in specific proportions to produce subatomic effects that we're only just beginning to understand in recent decades.
For some reason, the scientists weren't allowed to take this millennia-old relic and fill it with Tang and tequila (That's a TnT, and we heartily recommend it) just to see what happened. So they did their best to replicate it and found that it would probably also have changed colors based on what kind of liquid was poured into it. It's a Hypercolor chalice! What's more, it's even more effective at detecting different kinds of substances in water than modern sensors are, which means that science is actually considering using a piece of technology from the time of Caesar to improve modern substance detectors. The Ancient Romans were so good at getting drunk that they broke the science of the future.