These miscellaneous agate beads don't fit neatly into any of our other agate bead categories and are limited to stock on hand. Don't wait to buy these semiprecious beads and be sorry later! Agate beads are made from a variety of chalcedony and are composed of quartz layers that can vary greatly and consist of many colors. Typically translucent, agate beads are composed of microscopic "fibers" of crystalline quartz. Here you'll find gray agate (grey agate), black agate and other oddballs that might just be the perfect thing for your latest jewelry application.