Candy Geode Recipe
Geodes are crystal-filled, hollow rocks. Many rock collectors, children, and geologists delight in finding geodes, which form from gas bubbles in sedimentary rock or in volcanic rock. In the United States, they are most commonly found in the states of Utah, Missouri, Iowa, Indiana, and Kentucky.
Geodes can be hard to find, but simulated geodes are simple to make. This recipe is for an entirely edible geode, made from sugar crystals and chocolate. This candy would be a fun treat at a gem-themed birthday party, science class, or to simply surprise a rock-hound!
Be sure to plan ahead when making candy geodes: the sugar crystals take 2 days to form, so the candy must be made in advance. Make sure you have a space cleared out in a dark cupboard, so the sugar syrup solution has a place to sit, undisturbed, for a full 48 hours. In some cases, the crystals may take more than 48 hours to form.
Sugar Crystal IngredientsClick thumbnail to view full-size
- 2 cups water
- 4 cups sugar
- food coloring
- 1 bag white candy melts
- 2 tbsp unsweetened cocoa powder
- cooking spray
- aluminum foil
- small bowls
- plastic wrap
Rock Candy Geode Video
How to Make Sugar Crystals (Rock Candy)
The edible crystals inside of the candy geode are made from sugar. As with any other "rock candy" recipe, twice as much sugar as water is required. This recipe will require:
- 2 cups of water
- 4 cups of sugar
- Food coloring (optional)
While food coloring is not required for the recipe, it is highly recommended to create colorful, bright crystals that resemble amethyst and other crystals found in real geodes.
- Add 2 cups of water to medium saucepan. Bring the water to a boil.
- Add the sugar, one cup at a time. Stir the sugar until it is dissolved.
- Remove the syrup from its heat source, and stir in food coloring, if desired.
If several different colors are desired, pour the syrup into 3-4 bowls and add food coloring to each bowl. Tint each bowl of syrup until it is quite dark, as the final crystals will be lighter in color than the wet solution.
Candy Geode CrystalsClick thumbnail to view full-size
Forming the Geode Crystals
The sugar syrup must be poured into foil-lined bowls to create the crystalline interior of the candy geode. For this step in the process, you will need:
- Small bowls (12 "prep" bowls were used for this recipe)
- Aluminum foil
- Cooking spray
- Simple sugar syrup
- A dark cupboard
Cut the aluminum foil into squares that will fit inside each bowl. Press the foil into the bowls to create a liner. Spray each foil-lined bowl with cooking spray.
Pour the super-saturated sugar syrup into each bowl. Place the filled bowls into a dark cupboard and allow the solution to sit for 48 hours (2 full days).
Why the Crystals are Made First
Some people might think it would be easier to make the chocolate shell first - why not simply pour the sugar syrup into a pre-formed chocolate shell? At first glance, this appears to be a time-saving measure. Unfortunately, pouring the liquid syrup into a chocolate shell simply won't work: the syrup will dissolve the chocolate! The candy crystals must be made first, and the shell applied after the crystals have dried.
How to Make a Chocolate Geode "Shell"
- After 48 hours have passed, remove the sugar solution from the dark cupboard. Pour off the excess fluid. Gently peel the aluminum foil off the sugar crystal form.
- Next, melt white chocolate candy pieces in the microwave. Microwave the candy melts in short bursts, 10 to 20 seconds at a time, stirring frequently.
- Turn the crystal geode form upside down on a piece of wax paper. Use a paintbrush or a butter knife to gently coat the back of the crystal form in white chocolate. Allow the white chocolate layer to dry.
- Add a tablespoon or two of dry, unsweetened cocoa powder to the melted white candy pieces. Adjust the amount of cocoa powder to achieve a brown color.
- Paint the brown chocolate layer over the white chocolate layer. Allow the chocolate to dry.
- Trim the edges of the chocolate layers with a serrated knife to form an even edge.
Adding the Chocolate Shell LayersClick thumbnail to view full-size
The Finished Edible Geode
Once the candy geode is completed, store the candy in a cool, dry location. Humidity will cause the sugar crystals to disintegrate, and heat will cause the chocolate shell to melt. For a fun gift, wrap the geode in plastic wrap and place a nice label on the package. For a party, display the geodes under a bright light to show off the beautiful crystals!