Kerkaion was the staff of power associated with the Greek god Hermes(we are all more familiar with its Latin translation, caduceus). There are several interesting stories on the origins of this staff but the one that appears to represent it well is of prophet Tiresias who was forced to carry out the dual existence of a man and a woman.
Although Rick Riordan, the author of the Percy Jackson stories, brilliantly depicted the entwined snakes on the rod as George and Martha(suitable names for their mythological associations) I personally think of the two serpents as the transformed Kadmos and Harmonia of the Theban cycle.
I deduce the symbolism of the Hermetic rod to contain such diverse ideas as synthesis, reconciliation of opposites, the whole being greater than its parts, and proper responsibility as means to self realization.
Beachside is a seller on ebay from whom I have bought the caduceus(inexpensively) and enjoying expending my rod collection ever since. Below you can find another, perhaps less familiar but equally delightful sample of the Beachside jewelry with which I was very pleased. I discussed several other pieces in my collection in a youtube review(https://www.youtube.com/watch?v=PKrilitLb_M) for those who wish to see more details, but my general motto is: there can never be too many caducii. LOL and beachside has many more jewelry pieces to offer for fans of the mythological/supernatural or simply quaint.