Large Crack Open Geodes Set of 2, Geology Info & Bag

These nifty geodes are every little boys' dream and are great for hands on learning of basic Earth geology. Crack these geodes open and find out what's inside! Each set comes with free geological info, safety instructions. Geodes are geological rock formations which occur in sedimentary and certain volcanic rocks. Geodes are essentially rock cavities or vugs with internal crystal formations or concentric banding. The exterior of the most common geodes is generally limestone or a related rock, while the interior contains quartz crystals and/or chalcedony deposits. Some geodes are completely filled with crystal, being solid all the way through. Set of 2 geodes. Sizes vary from 1.5 to 2.5 inches. Crystallization varies.