Crystal Egg Geodes
Geodes can be grown without using egg dye. The resulting crystals are clear to milky white, like quartz. While large chicken eggshells are suggested in this process, larger eggshells can be used. Simply increase the size of the plastic or glass container and double or triple the amounts of dye (1 packet), alum (3/4 part), and water (2 parts) used to create the growing solution.
This Easter craft from Jim "Figgy" Noonan doubles as a science project, offering an opportunity to show kids the crystallization process at work. To make a fluorescent variation for Halloween, substitute the water and egg dye solution with glow water.
Resources: If you don't want to blow your own egg or would like to try a larger eggshell, pre-blown shells are available from The Eggery Place. Alum is available at most grocery or drug stores but can also be purchased online from Talas. Powdered egg dye is available from Surma: The Ukranian Shop. Ready-made Crystal Egg Geode kits available from Professor Figgy's Fabulous Science Kits at professorfiggy.com.