This black (dyed) agate lends a splendidly sophisticated air to any outfit, and will look stunning with Swarovski crystal beads! Because this is a natural stone, colors and patterns will vary from bead to bead. Special Purchase stone, quantities limited to stock on hand Agate is a banded member of the quartz family. Agate, one of the oldest known gems has been valued for thousands of years. Agate is reputed to aid insomnia and sweet dreams. Other members of the quartz family include jasper, carnelian and onyx.