Symbols are images and shapes which carry meaning, and are part of the first signs of advanced intelligence. Some symbols are universal, some are obscure, but all are evocative. Many last for centuries, and some are meaningful for only a short time. Early civilizations used symbols called hieroglyphs to write with, and our letters themselves are a sort of symbol.
Wearing symbols as jewelry keeps the symbol's meaning close to the wearer, in both physical and mental spheres.