This project covers how you can use a chicken egg, Elmer’s glue, alum, a large plastic container (the size of a quart jar), water, and egg dye to make a real looking geode. Depending on what type of gemstone you’re looking to make, you’ll need to have that color of dye to make the color of your gemstone geode. Purple for amethyst, Red for garnet or ruby, blue for sapphires, and so forth. This method of crystal production doesn’t take as long as making a large crystal, which can take up to 3 weeks.
Here’s what you’ll need:
- Elmers Glue
- Alum Powder
- Quart sized container (disposable plastic soup containers work well)
- A paintbrush
- Chicken eggs (blown out and gently broken in half the long way for a shallow bowl or broken in half the short way for a deeper geode.)
- Very hot water
- Egg Dye (The better the egg dye the deeper the color of your crystals.)
- A large wooden craft stick
- Latex Gloves
- Drying Rack
- Kitchen Tongs or Spoon
- Sewing needle
Step 1: The first thing you will need is a (washed) chicken egg. Take a needle and make a small hole in the top and bottom of the egg then gently blow the yolk and egg white out of the shell. This will take some time, but be patient … it is worth it!
Step 2: Next, take a pair of sharp scissors and carefully cut the eggshell in half lengthwise. Then rinse the inside of both shell halves with warm water until clean. Remove any loose shell chips and use a tissue or paper towel to blot excess water out of the shell. Be sure to let the egg shell halves dry in the open air (6 – 12 hours or overnight). The shells need to be clean and dry before proceeding to step 3.
Step 3: Pour in some Elmer’s glue and use the brush to paint the inside and the edges of your eggshell with the glue. Then sprinkle dry alum powder inside the shell to coat it completely. Don’t be shy about how much alum powder to put in the shell. What doesn’t stick will be removed in the next step (and reused for another geode if you wish). Set the egg aside to dry.
Step 4: Once the glue is dry, dump the excess alum out of the eggshell (on a piece of paper or in a bowl). You can gently tap the shell, but still be careful not to break the shell doing that, then proceed to the next step.
Step 5: Prepare the crystal growing solution by pouring of 2 cups of nearly boiling, hot water into your quart container. Put on your latex gloves (to prevent staining your hands) and add enough egg dye to the hot water for a deep color of your choice (or 30 to 40 drops of liquid food coloring). Stir the mixture with a large wooden craft stick until the egg dye (or food coloring) is completely dissolved and the solution color is uniform.
Step 6: Add 3/4 cup alum powder to your dye solution. Stir the mixture with the same craft stick used above until all of the powder is completely dissolved. (If you still have crystals undissolved in the container, microwave it for a few minutes to make sure it’s hot enough to dissolve all of the powder. But be careful not to let it boil over in the microwave. Just heat it until you see bubbles and stop, then carefully remove the container from the microwave and stir until the alum is all dissolved.
Step 7: Allow the solution to cool for about 20 to 30 min. Then use the tongs or a spoon to gently place one of the egg shell halves inside the container and submerge it in the alum and dyed water. Make sure the broken side of the shell is facing up and that it settled nicely on the bottom. Leave the egg shell in there for about 12 hours. (The longer the shell is in there the bigger the crystals will be in your geode.)
Step 8: After 12hrs or more, use a spoon to gently remove your eggshell from the solution. But be careful … wet crystals are very fragile! Place your geode on a drying rack to dry being careful to touch as little of the shell or crystals as possible until it’s completely dry.
Tip: (If you want to do the other half of the egg, simply microwave the leftover solution and stir well. Place another prepped eggshell half into the newly heated solution and wait another 12 hours. This project can be done with ANY egg. Try an ostrich egg for some seriously awesome geode!)
Also – You can prepare several containers, each with a different colors and make them all at the same time for your geode “collection”.
So What Just Happened?
We heated the water so it could become supersaturated with dissolved alum. As the liquid cools, it cannot hold as much of the dissolved alum, so some of it turns back into alum powder (or crystals) and sinks to the bottom. As it does that, it starts to crystallize. The powdered alum inside the eggshell acts like small seed-crystals, and the alum coming out of solution can attach itself to those quite easily. As more and more of the dissolved alum comes out of solution and settles to the bottom, the larger the crystals being formed will grow (to a point). Since they can start easier on the alum we put inside the eggshell, they grow faster there.
As an extension to this project, think of other things you might try instead of alum. Something that crystallizes … like maybe sugar or salt or even borax (and there are quite a few others).
… Or … if you prefer a kit for crystal growing, these should help:
… and if you decide you would rather find them yourselves, these should help: