DIY Giant Borax Crystals

Grow your own big borax crystal geode

Aqua Borax Crystals

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Giant borax crystals are perfect, whether you want to move on from borax crystal snowflakes or just want a big, beautiful crystal rock. These crystals can be grown in a geode shape or in multiple colors, making them great for mineral displays.

Giant Borax Crystal Materials

  • Borax
  • Water
  • Food coloring
  • Pipe cleaners (chenille craft sticks)

Borax is sold with laundry detergents as a natural cleaner. It's also sold as an insecticide, usually as a roach killer. Check the product label for borax or sodium tetraborate.

What You Do

The large size of the crystals comes from two things:

  • A structure or armature on which the crystals grow
  • Controlling the cooling rate of the crystal growing solution
  1. The first thing you need to do is bend the pipe cleaners the shape you want for your crystal "rock" or geode. For a rock form, you can simply twist several pipecleaners end-to-end and crumple them up into a rock shape. Neatness really doesn't count because you're going to coat the entire mess with crystals. For a geode, you can spiral pipecleaners into a hollowed shell shape. Either works fine. You don't need to completely fill in the open spaces with pipecleaner fuzz, but you don't want giant gaps either.
  2. Next, find a container slightly larger than your shape. You want to be able to set the shape in the container, without having it touch the sides, with enough space that you can completely cover the form with liquid solution.
  3. Remove the shape from the container. Boil enough water to fill the container enough that it would cover your pipecleaner form. Stir in borax until it stops dissolving. One easy way to make sure you have as much borax as possible in the water is to microwave the mixture back to boiling.
  4. Add food coloring. The crystals will be lighter than the solution, so don't worry if it seems deeply colored.
  5. Place the pipecleaner shape in the solution. You may need to shake it around a bit to dislodge air bubbles to make sure it won't float.
  6. This is where the controlled cooling come into play. You want the solution to cool slowly in order to get the largest crystals. Cover the container with a towel or plate. You can wrap it in a hot towel or place it in a warm location,
  7. Allow a couple of hours for the crystals to start growing. At this point, use a spoon to dislodge the shape from the bottom of the container. You don't have to do this step, but it seems to make it easier to remove the crystals at the end if they are loosened early. Let the crystals grow several more hours or overnight.
  8. Remove the form from the container. The crystals may be perfect now or they may be fairly small and incompletely covering the shape (most common). If they are fine as they are, you can let them dry, otherwise you need more crystals.
  9. Prepare a new solution, dissolving as much borax as you can in water, adding food coloring (doesn't have to be the same color), and sinking the crystal-covered shape. Fresh crystals will grow on the existing ones, larger and better-shaped. Again, slow cooling is key for best results.
  10. You can do another round of crystal-growing or finish the project whenever you are satisfied with the crystal size. Let the crystal dry on a paper towel.
  11. If you want to preserve the crystals to display them, you can coat them with floor wax or nail polish.
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Your Citation
Helmenstine, Anne Marie, Ph.D. "DIY Giant Borax Crystals." ThoughtCo, Apr. 5, 2023, Helmenstine, Anne Marie, Ph.D. (2023, April 5). DIY Giant Borax Crystals. Retrieved from Helmenstine, Anne Marie, Ph.D. "DIY Giant Borax Crystals." ThoughtCo. (accessed June 1, 2023).