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How to Make Iridescent Rainbow Crystals

Forget the leprechaun and his pot of gold and create your own magic by making iridescent rainbow crystals.


  • Step 1: Wait and watch as the colors produce a magical optical effect on the ice by creating iridescent rainbow crystals.
  • Step 2: Continue to observe the changes as the ice melts, or preserve the crystals in a cold place for future study. Look at the crystals from different angles and notice how the surface color changes -- that's the quality that makes the crystals iridescent. Even if you don't have a pot of gold, you've got a wealth of scientific know-how.
  • FACT: Rainbows in the sky must be viewed with the sun behind you.
  • TIP: Try neon food colors rather than using primary colors for a brighter, but less natural, rainbow.
  • Step 3: Color the ice by selecting a combination of colors and squeezing drops of food coloring directly from the bottles onto the ice. Don't worry about order or if the colors flow and merge.
  • TIP: You can use a large ice block, which you can buy from a commercial ice company, or make in a large freezer using empty cardboard milk containers.
  • Step 4: Sprinkle salt over the ice, varying the amount of coverage to achieve different effects.
  • Step 5: Place the ice chunks in a bowl or cup.

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