An afternoon in the Barnes & Noble to check out the Flash Bible left me with a stack of books referring to other more overtly sacred texts. Even if this meant I'm still sadly lacking in my ability to produce animation for this site, it did make for some fun reading.
Frank McCourt has a book out on the history of the Claddagh ring, beloved by millions of Irish descent, not to mention Buffy/Angel shippers (you know who you are!)
Spiritual Tattoo, a suggestive analysis of the anthropology of tattoos in relation to religious cultures.
Signs & Symbols in Christian Art by Ferguson--a basic reference on the subject of its title, but perhaps not exactly what a jewelry maker would be looking for as a comprehensive reference for design models.