I love this thing, and have worn it practically daily since I received it!
Here's what it means:
Symbol of the Earth Healer.
Symbols of healing and wisdom, serpents live within the depths of the Earth Mother and have mastery of all her secret knowledge and vital forces. Both Brigantia and Sironi, Celtic goddesses of healing, use the serpents' mystical powers to work their cures. Because of their wave-like movements, serpents are also associated with healing waters and scared wells, sources of regenerative powers from within the earth, thus protectors of health and well-being.