It’s simple to make gorgeous marbled eggs using olive oil marbling. Simply dye your eggs with food coloring and then marble them with a darker color. (Epsom Salt Egg Geode instructions are at the bottom of this post.)
Hint: Wear gloves to avoid staining your fingers.
-2 cups of warm water in a bowl
-hard boiled eggs
-food coloring (We used Wilton Color Right food coloring: 2 drops blue mixed with one drop of yellow in about a cup of water to make robin’s egg colors, and brown for marbling.)
1. Make base dye by adding a few Tbs. vinegar to two cups of water. To this, add a few drops of food coloring. Lighter colors work best for the base.
2. Dye the hard boiled eggs in the base color until they are the desired shade. Let them dry.
3. To a small bowl, add 1/2 cup water, a Tbs. of vinegar, darker food coloring, and 1/2 tsp olive oil. Add more oil if you want less dark color when you marble. Oil shouldn’t cover the entire surface.
4. Swirl the oil with a toothpick or spoon and lower your egg into the water/oil mixture, swirling and spinning it. When you like the results, take it out and let it dry.
5.When the egg is dry, remove the excess oil with a paper towel.
The science behind the fun: Food coloring is an acid dye, so the vinegar (acetic acid) helps it bond to the egg shell. Oil is less dense than water and floats on top. When you put the egg in the oil-colored water mixture, the oil coats part of the egg, preventing it from being stained.
Epsom Salt Crystal Egg Geodes:
Have an adult cut a raw egg in half lengthwise, using a serrated knife. Wash the shell and dry it. Dye if desired.
Use a glue gun or school glue to coat the inside of the egg. Sprinkle in Epsom salt crystals and allow to harden or dry.
(Warning: Hot liquids require adult supervision.) To make the Epsom Salt crystals, dissolve 3 cups of Epsom salts in 2 cups of water by heating and stirring until no more crystals are visible. This creates a supersaturated solution. Allow the solution to cool slightly. Fill each half eggshell with Epsom salt solution. When long, needle-like crystals have formed, dump out the excess liquid and break the thin layer of crystals on top to reveal the ones in the shell.