This project uses hot tap water, not boiling water, so it's safer for young crystal growers. Place the crystal solution in the refrigerator and get sparkly needle-like crystals within a few minutes to a few hours. It's that easy! 1/2 cup Epsom salt 1/2 cup hot tap water food coloring (optional) instructions here: http://chemistry.about.com/od/crystalrecipes/ht/cupofcrystals.htm
How to Grow Epsom Salt (Magnesium Sulfate) Crystals: Epsom salt is magnesium sulfate. It's easy to grow Epsom salt crystals. The crystals typically resemble shards or spikes. Initially the crystals are clear, though they whiten over time.
Home-made Geodes Required materials Epsom salts 2 cups of warm water 3 or more eggs (we only the shells) Food coloring (red, green, blue, and any other color you like) Large glass Spoon Knife (optional)