These are glass pendants, they are very popular at the street fairs. You can usually find a table in every block. They are also really cheap, most are $3 with $1 for the cord to hang them on. They are sold separately so you can match whatever color in the pendant you want with a cord. I have 3 that I got from street fairs and one that I got from a street vendor.

These are two of my necklaces. For some reason I keep getting heart shaped ones.