The tooth is polymer clay, you can see others I've made into earrings here: http://www.craftster.org/forum/index.php?topic=415137.0
I posted this here because it's less polymer clay and more of a mixed media jewelry piece.
This is tubing, fake blood, leather and of course polymer clay.
The "blood" oozes through the tubing and is fun to watch and play with...in a sinister kind of way. This is my signature bracelet and I have been making different variations.
With it being Halloween season I thought I'd share...
and some photos to show the effect better: