I've recently discovered mood beads and glass glow-in-the-dark beads
The mood beads change color to match your mood, but it's actually your
body temperature that changes the colors.
The glow-in-the-dark beads are glass, and they glow green (after being
in sunlight, or bright light).
Anyhow, they are fun to play with, so I've made a couple of
neat bracelets with them.
If you want to see them, go here: