How to Make a Glow in the Dark Crystal Geode

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How to Make a Glow in the Dark Crystal Geode

It’s very easy to make a glow in the dark crystal geode. The ‘rock’ is a natural mineral (eggshell). You can use one of several common household chemicals to grow the crystals. The glow comes from paint, which you can get from a craft store.

GLOW IN THE DARK CRYSTAL GEODE MATERIALS

You need a few simple materials for this project:

  • Eggs
  • Glow in the dark paint (I used GlowAway™ washable glowing paint)
  • Very hot water (I used my coffee maker)
  • Borax, alum, Epsom salts, sugar, salt, or use another crystal recipe
  • Food coloring (optional)

Note that most crystals exclude the glowing pigment from the paint as they form. In this project, the interior of the egg shell glows, illuminating the crystals from within.

PREPARE THE GLOWING GEODE

  1. There are two ways easy methods for cracking your eggs. You can carefully crack the top of the egg by tapping it on a counter top. This gives you a deep geode with a smaller opening. Alternatively, can crack the equator of the egg or carefully cut it with a knife. This gives you a geode you can open and put back together.
  2. Dump the egg or make scrambled eggs or whatever.
  3. Rinse out the inside of the eggshell with water. Peel away the interior membrane so you are left with only the shell.
  4. Allow the egg to air dry or carefully blot it dry with a paper towel or napkin.
  5. Use a paintbrush, swab, or your fingers to coat the inside of the eggshell with glowing paint.
  6. Set the painted egg aside while you mix the crystal-growing solution.

MAKE THE CRYSTAL SOLUTION

  1. Pour hot water into a cup.
  2. Stir borax or other crystal salt into the water until it stops dissolving and you see some solid at the bottom of the cup.
  3. Add food coloring, if desired. Food coloring does not get incorporated into all crystals (e.g., borax crystals will be clear), but it stains the egg shell behind the crystals, giving the geode some color.

GROW THE GLOWING CRYSTALS

  1. Support the shell so that it won’t tip over. I made a little nest for mine in a crumpled napkin that I set inside a cereal bowl.
  2. Pour the crystal solution into the shell so that it is as full as possible. Don’t pour the undissolved solid into the eggshell, just the saturated liquid. While the undissolved particles act as seed crystals and you get faster growth, they also produce smaller crystals.
  3. Set the shell somewhere where it won’t get knocked over. Allow crystals to grow for at least several hours. Some crystals require several days for full growth.
  4. When you are satisfied with the crystal growth, pour out the solution and let the geode dry.
  5. Phosphorescent paint glows after exposing it to bright light. Sunlight and black light (ultraviolet) produce a very bright and long-lasting glow. The duration of the glow depends on the paint you use. Some paints produce geodes that glow for a few seconds. Other paints glow for many minutes or even hours.
  6. Store your geode in a dry location, protected from dust.

GLOW IN THE DARK CRYSTAL GEODE TIPS

  • Instead of using egg shells, you can grow a geode on a rock or inside any hollow surface.
  • Try using plaster of Paris instead of an eggshell. An eggshell is calcium carbonate. It’s a great option for making a realistic geode, but you only have that “egg” shape. Plaster of Paris is gypsum or calcium sulfate. Mold it into any shape and let it dry before painting it and adding the crystal-growing solution.
  • You control the glow color! Experiment with different colors, even within a single geode.
  • Note that different colors do not glow with the same brightness or for the same duration. Generally, the brightest and longest glow comes from green, followed by aqua and blue. White, yellow, orange, red, and purple usually do not glow quite as brightly or as long.