Rondelle

A rondelle (or “roundelle”) is a circular disk of metal, gemstone or diamond and is usually inserted between beads on a strung or beaded necklace. The term spacer is also used to describe a rondelle.
Faceted Citrine Bead and Quartz Rondelle Necklace.

Faceted Citrine Bead and Quartz Rondelle Necklace.