Oh wow this is so cool this is one of the coolest things I have read in a while!

[conuly]

(Thanks, Siderea!)

The glass chalice, known as the Lycurgus Cup because it bears a scene involving King Lycurgus of Thrace, appears jade green when lit from the front but blood-red when lit from behind—a property that puzzled scientists for decades after the museum acquired the cup in the 1950s.

http://tinyurl.com/lm5jbbf

Comments

[steorra]

So, I was following up on the violin rosin thing again, as I do from time to time to try to figure out what was going on. (I rediscovered this post via a comment email while I was searching my email to see if I'd found and forgotten a solution, but this was all I found.)

I am wondering if what's going on with some violin rosin is actually the same effect as what's going on with the cup! I just read:

Some companies also add precious metals to their recipes—another choice to consider when shopping for rosin. It is not uncommon to see gold, silver, lead-silver, and copper added to rosin. These materials purportedly increase the rosin’s static friction, creating different tonal qualities.

Also, I'm kind of surprised that lead-silver isn't considered too dangerous to use. Rosin dust gets everywhere.

[conuly]

I'm astonished too.