Take your polymer clay out of the packaging and knead it with your hands to warm it up to make it easily malleable. At this point, decide what color you want your geode to be. You can use one solid color or multiple colors to give it a marble effect. If you choose a marble look, twist the clay until the colors are intertwined but not completely blended. Then, flatten the clay and form it into a small bowl-like structure. Don't worry about making it perfect! The more imperfect it is, the more realistic the geode will look.
Bake your clay according to the instructions on the package. You want the bowl to be firm but not completely brittle. Once your bowl is finished baking, let it completely cool before moving onto the next step.
This is where your geode will really start to shine! Add a spoonful of alum powder to the inside of the bowl and shake it around to evenly distribute. Once finished, let your alum-covered geodes dry before moving on.
Add 10 to 20 drops of food coloring to the alum concoction and give it a stir. The food coloring doesn't have to match your bowl, either! In fact, mismatched colors make for a more interesting, natural-looking geode.
This video from YouTuber Ann Le will give you the full step-by-step lowdown.
These faux geodes are so easy to create and look so realistic, no one will believe you made them yourself. Give them as gifts, spruce up your decor or even frame them! This DIY is just too rockin' to pass up.