Anomalous Bits has a quite a varied selection to choose from, and the waterproof plastic pendants really look like antique glass. They are so inexpensive, but they don't look that way. The ink is actually burnt into the plastic, so the images won't scratch off.
Here is a size scale. I don't like big, bulky jewelery, so I think Anomalous Bits' pieces are just right. The plastic is so lightweight, too, you don't even feel like you are wearing anything.
For those of you out there who would like to see your own images on this type of pendant or earring, Anomalous Bits can do that for you! Custom pendants are just $5!