DIY Crystal Egg Geodes

Try this experiment to grow your very own crystal geodes in an eggshell!

Easter is just around the corner, and I've got fun (and educational) project you can do with the kids over the weekend! It's not your typical Easter craft, but your kids are going to love it. After peeling your colorfully dyed Easter eggs, save the shells to create some gorgeous geode-like crystals. Kids will have a blast helping throughout the process, and the results are amazing! I hope you have a great time doing a little bit of Easter science!

This egg crystals craft is part of Creative Crafts: Quick & Easy Easter Crafts Edition! Creative Crafts is a series hosted by Me and My INKlings, Makeable Crafts, Creatively Beth, and Bella Crafts Publishing where some of your favorite crafters come together to create crafts around a specific theme! Be sure to check each of the host blogs for more Easter craft ideas!

To make your own Eggshell Crystal Geodes, you will need these supplies:

• Eggshells, washed and dried
• White School Glue
• Alum (aluminum sulfate)
• Paint Brush
• Food Coloring
• Water
• Measuring Cups
• Microwave-Safe Container
• Spoons or Craft Sticks

Crack your eggshells in half. If your eggs are boiled (from Easter) you can crack them in half horizontally (the "traditional" way), or you cut the shells in half vertically using some small, sharp scissors. If you aren't using boiled eggs, you can blow out the egg and then cut the shells in half vertically using scissors. Honestly, it doesn't matter which option you choose, but cutting them vertically gives you more area to cover. 

Wash the eggshells out well and leave them to dry completely. If the kids are helping with this step, just remember to be very careful because they're very fragile!

Coat the inside surface of each eggshell half with a thin layer of glue using a small paint brush. Sprinkle a little bit of Alum powder* over the glue until covered, the same way you would with glitter. Work over a garbage can to keep the mess to a minimum.

*Alum powder is mostly used in pickling recipes, so it's safe to use. However, I do recommend washing your hands thoroughly after using it.

Set the eggshells aside and allow them to dry overnight. I cannot stress how important this step is. If you don't wait, the crystals will not form correctly, if at all.

Heat 2 cups of water to almost boiling in the microwave or in a saucepan on the stove. Pour the water into a microwave-safe container. Slowly stir in 3/4 cup of Alum powder and stir the mixture with a spoon or stick until **completely** dissolved.

Add in 30 drops of food coloring into the mixture, and stir to combine. If you want multiple colors of egg crystals, split the water mixture up into different glass jars or cups and then add colors to each cup. I recommend using glass or something disposable, because this will definitely stain!

Let the water mixture cool for about 30 minutes. Carefully submerge an eggshell into the mixture. It should sink to the bottom, with the inside of the shell facing up. Place the container(s) in a safe place to sit undisturbed overnight. I recommend leaving the shells for at least 12 to 15 hours for incredible geodes.

**If you keep stirring and the alum is not dissolving, put the mixture back into the microwave for a minute or two to heat it back up. Any undissolved alum will start forming crystals in the bottom of the container instead of on your egg, which is a bummer. So, keep heating and stirring!

Use a spoon to CAREFULLY remove the shells from the mixture and place them on a few paper towels, newspaper, or scrap paper to dry. Wet crystals are VERY fragile, so try your best not to handle them too much!

I love how vibrant the eggshells are from absorbing all of that coloring, and the crystals are SO cool! Each one is so different. If you want to keep making more and more eggshell crystals, you can reheat the water mixture to dissolve the remaining crystals to start the process again!!

The Science: Geodes are rocks with crystals inside. When gas bubbles become trapped in molten rock, sedimentary rocks become hollow on the inside. Minerals that dissolve in the water will seep into the empty space in the rock and slowly deposit to form crystals.

With the eggshells, the alum sprinkled on the glue acts as "seeds" for the crystals. Dissolving the alum in hot water created a “super-saturated solution.” As the solution cools, the crystals become solid again, attaching themselves to the crystals on the eggshells. Since this happens slowly, along with evaporation, the crystals have more time to grow larger than they were when the experiment started.

It was a lot of fun for us to do together as a family, and hope you are inspired to try it for yourself. As always, I would love to see your creations if you make these for yourself! Leave me a comment, or tag a photo on Facebook, Twitter, or Instagram! #AFMcrafts

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