A type of bead (or a bar or plaque pierced at intervals) that is threaded on a necklace or neck chain made of multiple strands so as to ensure that the strands will remain separated and correctly spaced in relation to each other. Among the earliest known examples are some found in a girdle from Egypt, c. 4000 BC. Others were made of Tairona jewelry. Such beads have been made of various materials and in many shapes. An ornament strung on a necklace to separate various large decorative objects.
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson