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Coral Undersea Crystal Garden

Easy To Grow Colorful Crystals


The coral crystal garden is an interesting version of the classic bluing crystal project.

The coral crystal garden is an interesting version of the classic bluing crystal project.

Anne Helmenstine
This is a colorful and interesting crystal project that resembles an undersea scene. The crystals look like delicate coral.


  • 3 tablespoons household ammonia
  • 3 tablespoons iron(III) ferrocyanide solution (Mrs. Stewarts Laundry Bluing) [shop online]
  • 1 tablespoon table salt
  • food coloring or water soluble markers
  • cardboard or construction paper
  • scissors
  • shallow dish or plate


  1. Cut out the paper or thin cardboard so that it resembles a coral undersea grotto. Be creative!

  2. Color your scene with water soluble markers or dot it with food coloring. You do not need to completely cover the scene because the crystal growing solution with spread the colors outward.

  3. Prop up the scene on a plate or shallow dish.

  4. Mix together the ammonia, bluing (iron ferrocyanide solution) and salt.

  5. Dribble some of the solution onto the paper scene. Pour the remainder into the bottom of the dish so that the paper can absorb it.

  6. Set the undersea scene somewhere that it won't get bumped or disturbed. The crystals will grow over the next several hours. Expect your crystal scene to be complete overnight or within 1-2 days. The length of time depends on temperature and humidity. The solution will evaporate more quickly when it is warm and dry. If you like, you can add more crystal growing solution to the base of the scene.

Caring for the Crystals

You can keep the crystals when they are done growing, but expect them to lose some structure over time. Fragile crystals may break off or the salts may re-dissolve under high humidity. Sunlight and extended exposure to fluorescence light may fade the colors. If you plan on keeping the crystals, store them in a shaded dry location, away from drafts, direct sunlight or vibration.

Watch a video of the growing crystals.

Related Crystal Projects

Salt Crystal Garden
Charcoal Crystal Garden

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