NATIONAL GEOGRAPHIC Break Open 10 Premium Geodes &ndash; Includes Goggles, Detailed Learning Guide and Display Stand DISCOVER CRYSTAL TREASURE when you break open these rocks to find amazing crystals inside! COLORFUL VARIETY of hand-selected geodes for interesting, vibrant crystals 100% NATURAL GEODES may be as big as a tennis ball or as small as a ping-pong ball and are the perfect size for kids 16 PAGE FULL-COLOR LEARNING GUIDE describes how geodes are formed and details the variety found in nature 100% SATISFACTION GUARANTEED - For 129 years, National Geographic has provided fascinating and fun educational opportunities to aspiring scientists around the world