Charcoal Crystal Garden

Crystal Garden (Anne Helmenstine)

Crystal Garden (Anne Helmenstine)

This is a classic crystal-growing project. You use charcoal briquettes, cardboard or a sponge, ammonia, salt, bluing, and food coloring to grow a crystal garden. The components of the garden are not edible, so adult supervision is recommended.

Materials

  • charcoal briquettes, cardboard, or pieces of sponge or porous rock
  • water
  • table salt (sodium chloride)
  • ammonia
  • laundry bluing agent
  • food coloring
  • glass dish or shallow bowl (non metal)
  • measuring spoons
  • clean glass jar

Step-by-Step

  1. Gather your materials.
  2. Place chunks of your substrate (i.e., a cardboard scene, charcoal briquette, sponge, cork, brick, porous rock) in an even layer in the non-metal pan. You want small pieces, so you may need to (carefully) use a hammer to break the material up.
  3. Sprinkle water, preferably distilled, onto the substrate until is has been thoroughly dampened. Pour off and discard any excess water.
  4. In an empty jar, mix 3 tablespoons (45 ml) uniodized salt, 3 tablespoons (45 ml) ammonia, and 6 tablespoons (90 ml) bluing. Stir the mixture until the salt is dissolved.
  5. Pour the mixture over the substrate layer (over the scene, brick or sponge or whatever).
  6. Add and swirl a bit of water around in the empty jar to pick up the remaining chemicals and pour this liquid onto the substrate, too.
  7. Dot drops of food coloring here and there across the surface of the ‘garden’. Areas with no food coloring will be white.
  8. Sprinkle more salt (about 2 T or about 30 ml) across the surface of the ‘garden’.
  9. Allow your ‘garden’ to grow in an area where it will not be disturbed.
  10. On days 2 and 3, pour a mixture of ammonia, water, and bluing (2 tablespoons or 30 ml each) in the bottom of the pan. Try to avoid pouring liquid on the delicate growing crystals.
  11. Keep the pan in an undisturbed place, but check on it periodically. Let it grow until your are pleased with its appearance. Enjoy!

Tips

  • Bluing is found in the laundry aisles of some grocery stores. If you can’t find bluing at a store near you, it is available online.
  • The crystals grow quickly for this project because the substrate (charcoal or whatever you chose) has a large surface area. Crystals start to form on the porous materials and then grow as capillary action draws more fluid up from the dish. Water evaporates on the surface, depositing solids/forming crystals, and pulling more solution up from the base of the dish.


2 thoughts on “Charcoal Crystal Garden

  1. Sarah

    Is it dangerous for a pregnant woman to be around this? A teacher next door did this with bituminous coal and it smells awful. I’m worried the smell could be harmful to my baby..,,,

    Reply
  2. Pingback: Grow Table Salt or Sodium Chloride Crystals | Science Notes and Projects

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