Surely intended for the use of a monk, this pendant represents a head divided to depict a monk on one half, and a skull on the other, making explicit the user’s own mortality and the certainty of death. The carver conveys the reality of impending death in the monk’s eyes rolling into his head, his parted lips, and his pallor, which is suggested by the natural color of ivory.
http://art.thewalters.org/detail/5036/pendant-with-a-monk-and-death/