Agate candy slices

Reward: Shake Up Bronze!

  • Variety of hard candies, 5 of each
  • Zip top bags (plastic bags)
  • Tinfoil (aluminum foil)
  • Kitchen mallet or rolling pin
  • Cutting board or hard surface
  • Cookie sheet
  • Small bowls and spoons
  • Small paintbrush, optional


To make our own DIY Agate Slices, break up a variety of hard candies into “crystals,” place them in homemade rock molds and then put them under heat to change their physical appearance.

This is a really cool kitchen science experiment that shows examples of both property changes and chemical changes – you are about to change the physical structure of the candies by smashing them (property change) and creating new bonds between different types of candy under heat (chemical change).

  • Preheat your oven to 300F
  • Form your agate crystal rock molds by folding a 6″ length of tinfoil in half and turning up the edges, shaping into a «bean shape.» Look at examples of agate crystals on Google for inspiration.
  • Place the tin foil molds on your cookie sheet and set aside.
  • Select a variety of different colored candies and unwrap them all.
  • Place all of the candies into separate zip-top bags.
  • And smash them into small pieces with a kitchen mallet or rolling pin.
  • Place all of the smashed candies into small bowls with spoons.
  • Fill in your agate crystal molds by spooning small amounts of the crushed candies into rings. We found it easier to work from the outside in after getting frustrated with a couple working from the inside out.
  • Make sure there are no empty spaces and your candy ring layers are not too thin. Ours was about 1/8″ thick but you can make it even thicker. (Too thin and they will snap easily.)
  • Bake them for just 3-5 minutes, watching carefully.
  • Remove them from the oven as soon as the crushed candies seem melted.
  • Let them cool on the cookie sheet and then carefully remove the tinfoil molds.