How to Grow Eggshell Geode Crystals
There’s something magical about crystals. Now you can grow your very own using this eggshell geode science experiment.
REMEMBER: always ask permission from and supervision of a grown-up before trying this experiment
What you need:
1 - 2 eggs
1 cup water
Iceblock sticks
A jar
PVA glue
Plastic cups
Food colouring (optional)
Paintbrush (optional)
4 tablespoons of Borax
Borax (sodium tetraborate) is a mineral salt that is commonly used as a laundry booster.
As with any cleaning product, do NOT eat borax and avoid prolonged contact with skin. Wash your hands thoroughly after using the borax or touching your crystal eggs.
What to do:
Crack the top of your egg and tip the contents into a bowl.
Don’t let your egg white and egg yolks go to waste! We used ours to make poached eggs on toast for lunch.Rinse the eggshell under warm water and carefully remove the egg membrane (a thin layer that lines the inside of the eggshell).
Use your finger or a paintbrush to gently paint the inside of the eggshell with glue.
Sprinkle borax inside the eggshell, over the glue, ensuring that all sides are coated.
Remove any excess by tipping the eggshell upside down.
Note: This process is called seeding. By coating the inside of your eggshell with borax, you are providing surfaces on which the crystals can grow.While the glue dries, fill a glass jar with 1 cup of water. Add 4 tablespoons of borax and stir to combine.
Microwave the jar for approximately 2 minutes (or until the solution goes clear), stopping every 30 seconds to stir the solution.
Note: Be careful! The water and jar will get hot, so make sure you ask a caregiver to help you with this step.Once the borax solution has cooled to room temperature, fill the plastic cups(s) with enough solution to completely submerge your eggshells in.
To grow coloured crystals, add a few drops of food colouring to each cup and stir gently with an iceblock stick.
Gently lower your eggshell into the borax solution and leave it in a place where your cup(s) won’t be disturbed for 48 hours.
Note: the longer you leave your eggshells the larger the crystals will grow.Once you are happy with the size of your crystals, carefully remove the eggshells from the solution and place on a paper towel to dry.
Experimenting further:
You can grow many different types of crystals at home. Try the experiment again using Epsom salts instead of Borax. Which works best? Do different solutions grow different shaped crystals?
After 48 hours making more borax solution and topping up your plastic cups with it. Does this grow more crystals?
Leave your eggshells in the crystal solution for a week. What impact does this have?
Explaining the Science behind Eggshell Geode Crystals
What are geodes?
From the outside, a geode looks like any other rock. However, on the inside, they are packed with crystals.How does the borax solution make crystals?
When you add borax to water and then slowly heat it you create a supersaturated solution. The hot water causes the water molecules to move further away from each other so the borax is more dissolved in the liquid than would normally be possible without heating the water. It becomes supersaturated.
As the solution cools, the water molecules come close together again. This causes borax crystals to form and cling to the eggshell.
Did you give it a go?
Send us a photo of your eggshell geodes and you might find it featured in a future issue of Upstart magazine… AND win a prize!