DIY: How to Make Crystals

Imagine learning how to make crystals? Well, now you can. I wish my parents knew about crystal egg geodes when I was little because I’m thinking about making them this weekend. This is a really cool science experiment to try out with your kids because it teaches them about growth and chemical reactions – but most importantly, patience! This science project takes a few days depending on how large you want your crystals but it is absolutely worth it! You kids can watch the progression of crystals forming hour by hour, day by day.

You’ll Need

Eggshell or Plastic Easter egg
Alum powder
White glue
Small paintbrush
Plastic or glass container
Egg dye
Hot water
Craft stick or spoon
Latex gloves
Drying rack or newspaper

Directions

Start by saving egg shells that are split across the middle as evenly as you can get them. You can also use those plastic Easter egg shells or trying blowing out an egg – which is a little bit more work, but you can split the egg vertically which is also quite nice.
Using a small paintbrush, apply white glue to the inside and cracked edges of each half of the eggshell, sprinkle the glued egg with alum powder until it is completely coated. Be sure to let the eggshells dry overnight.
The next day, prepare your growing solution in a glass or plastic container by using a popsicle stick or spoon to mix 2 cups of very hot water (nearly boiled) with an entire packet of powdered egg dye. Remember to wear latex gloves so you don’t end up coloring your hands too. You can also use liquid food coloring — 30 to 40 drops will adequately saturate the solution.
Add 3/4 cup of alum powder to the hot dye bath and stir until the alum has completely dissolved. If you find that there are crystals in the bottom you can place the solution in the microwave for a few minutes to dissolve them. This will prevent alum from being drawn away from the geode.
Once the alum is completely dissolved, let the solution cool a little for around 30 minutes. and then submerge one of the dried, alum-coated eggshells in the growing solution, let the shell rest on the bottom of the container with the inside of the shell facing up, overnight.
If you’re looking to create large crystals, the longer the eggshell is in the solution, the larger the crystals in the geode will be. 12 to 15 hours will usually result in a perfect geode.
The next day, remove the geode from the growing solution very carefully because the geode will be very fragile. Remember to wear latex gloves to prevent the dye from staining your hands. If your kids want even larger crystals, simply return the geode to the to the growing solution and wait a day or two. As water evaporates from the solution, more alum will be deposited in your geode, increasing the size of the crystals.
Place the geode on a drying rack or newspaper and allow to dry completely before handling.