Create natural sophistication in your designs with the sardonyx 10x14mm large-hole barrel beads from Dakota Stones. Available by the strand, these gemstone beads will amaze and delight with their innovative design. Each bead features a wide stringing hole, perfect for using with thicker stringing materials like leather cord. In fact, these beads are temporarily strung on leather cord. These cylindrical beads feature gleaming black color striped with white. Sardonyx is an onyx characterized by parallel lines of sard and different colored minerals. It is a distinct and dramatically banded variety of chalcedony composed of quartz layers. Mined all over the globe and also known as tuxedo agate, it is believed to improve memory.