Grow-Your-Own Geode Replica
You will need: a clean eggshell, paintbrush, glue, food coloring, alum powder, water, paper towels, glass jar, spoon
- With a paintbrush spread glue over the entire interior surface of a clean, dry egg shell all the way to the edges. Cover completely with alum powder. Set aside and let glue dry overnight.
- The next day, bring two cups of water to almost boiling. Pour into a beaker or glass jar and stir in 40 drops of food coloring and 3/4 cup alum. Allow solution to cool 30 minutes.
- Once cool, with a spoon, push egg shell (opening up) to bottom of solution. Set aside jar undisturbed for 12-15 hours. Then pull egg shell from solution and place on a paper towel to dry. Clean up!
What is a geode?!?
Geodes are usually formed in “bubbles” and other cavities in both igneous and sedimentary rock. Mineral-rich groundwater or rainwater slowly seeps through the porous rock and mineral layers are deposited in its hollow interior. Over thousands of years, these layers of minerals build crystals, eventually filing the cavity. Some geodes look like miniature caves.