Potomac Crystal Cylinder - Alexandrite AB. The crystal cylinder is a 1 hole bead that has a beautiful faceted surface that gives it a wavy, delicate look. Perfect for adding a little extra bling to your beaded projects, the crystal cylinder can help you fill those troublesome elongated spaces. Use it in place of bugle beads to create more dazzling crystal shine in your designs. The Potomac Crystal Cylinder measures 2.5x4.5mm and has a .8mm hole. Comes in a pack of 100.