Roses Brands®

Geode Cake Tutorial




Materials & Supplies

  • Roses Brands® Amethyst Gems
  • Roses Brands® Clear Crystals
  • Roses Brands® Amethyst Crystal Sticks
  • Two 5” round cake layers
  • Two 8” round cake layers
  • One 5” round waxed cake circle, one 14” round cake drum
  • Buttercream
  • White & purple fondant
  • Piping gel
  • Vodka (high proof)
  • Gold & silver luster dust
  • Royal purple airbrush (optional)
  • Offset spatula
  • Straight pins
  • Wooden cake dowels
  • Paring knife
  • Craft knife
  • Fondant smoother
  • Rolling pin
  • Tweezers


Torte, ice, and fill your cakes. Each tier height should be about 5.5” high. Let them chill in the refrigerator overnight. Your cakes should look like this.




Print and cut out the recessed geode template.



Pin the geode template to the bottom tier & trace it lightly with your paring knife to mark the area of the cake that you’ll cut out to create the recessed geode area.


Using the traced line as your guide, insert the paring knife at an angle. Be careful not to go too deep into the cake.


Remove the portion of cake you just cut out, it should look like this.


Repeat this method on the top tier using the same template, but this time also use a craft knife to cut away the cake board.


Next we’ll marble the fondant. For the 5” tier you will need about 20 oz of white fondant and a bit of purple fondant. Roll the white fondant into a log shape and place thin, long strips of the purple fondant on the white fondant log.  Push those purple strips into the white log:


Now twist the fondant log:



Bend the fondant log into a u shape, then twist again:


Repeat the process of bending the log into a U shape and twisting about 5-10 times or until you like the way your colors are blending. Now you’re ready to roll out your fondant.


Using a rolling pin, roll out your fondant big enough to cover the 5” tier (about a 17” circle).


Spray your cake with water (or a 50/50 mix of water and piping gel) using a spray bottle. Pick up your rolled out fondant with your rolling pin and drape your sheet of marbled fondant over the cake and smooth it out. Then cut away the geode cavity using your craft knife. Smooth a bit of buttercream on the exposed cake with your offset spatula.

The cake should look look similar to this:


Repeat this process for the 2nd tier. You’ll need about 28 oz of white fondant and a bit of purple fondant for the 8” tier.


Next we’ll stack the cakes. Measure, cut, and insert 4 dowels into the bottom tier.


Spread a layer of icing over the dowels.

Insert a sharpened cake dowel into the top right side of the 5” tier then use an offset spatula to lift the cake while holding the cake dowel to help with stabilization.  Place the 5” cake on top of the 8” cake and push the dowel all the way down into the bottom tier. Later we’ll cover the hole made by the dowel with rock candy sticks.

Now we are ready to add the rock candy and start creating the geode look. Roll out a piece of white fondant the same thickness as the marbled fondant and use the recessed geode template to cut the shape out. To attach the fondant to the cake just brush a bit of water on the buttercream on the recessed geode area and place the white fondant cut out in that area. Use a paintbrush to paint the white cut out with a 50/50 water and piping gel mix.

Using the tweezers, place the amethyst Roses Brands® rock candy gems in the center of the recessed geode area. Push the rock candy into the white fondant to secure it.  Follow the shape of the recessed area.

Next place the Roses Brands® clear crystals around the amethyst rock candy, be sure to cover the seams with the candy. Place the cake back in the refrigerator for a few hours to set the rock candy into place.


With a small brush, use a mixture of silver dust and high proof vodka to paint around the edge of the geode recess. Now mix gold dust and high proof vodka together and paint around the edge of the silver.  

Pipe a bead of buttercream around the base of both tiers & adhere the Roses Brands® clear rock candy gems to the bead of buttercream.

To mask the the exposed dowel on the top tier, insert Roses Brands® Crystal Sticks rock candy sticks and Rock Candy Gems near the dowel. If you have an airbrush machine you can also airbrush a royal purple color between the amethyst and clear gems to create a gradient look.