Unusual Red Sea Bamboo 9mm Coral Cube and Round Bead StringPrice is for 15. 5 inch of these beads. Each measures 9mm x 9mm cube beads alternating with 5mm round red coral beads. There are about 31 cube beads in a string. Coral is a natural water related bead that will sex up your summer jewellery! What Is Coral Coral is not a true gemstone, but a product of marine life the outer skeleton of sea polyps, made of calcium carbonate. However, it's been used as a gem since prehistoric times. History Coral is one of