Crystal Garden

• Begin your crystal garden by obtaining three charcoal briquettes. Grease the edges of a shallow bowl or tray with Vaseline in order to prevent crystals from growing over the sides. Place the charcoal inside this tray. Add several drops of food coloring or colored ink along the top of the briquettes if you wish to create colored crystals. In a separate glass beaker, mix 1/4-cup water, 1/4-cup liquid laundry bluing, 1/4-cup table salt and 1-tablespoon ammonia. Carefully pour this solution over the charcoal. Set the tray aside and observe at least twice a day until all the liquid evaporates. A flower-like crystal growth should appear after a day or so, but crystals will continue to grow until all the liquid evaporates.
  
  

Chemistry Behind Charcoal Crystals

• Crystals have a repetitive pattern of aligned molecules. When certain solutions become supersaturated, meaning they hold more molecules of a dissolved crystalline solid than the liquid can contain, the molecules rigidly structure themselves and form solid crystals. In the case of charcoal crystals, salt molecules from a liquid solution join into a crystalline structure as the liquid evaporates. Ammonia speeds up the evaporation, while the Ferric Hexacyanoferrate in liquid bluing contributes iron salts that help form the crystals. The charcoal also helps speed up the evaporation. More importantly, it provides a porous material for the crystals to form on.
  
  

Crystal Tree

• A similar crystal formation can occur even without the charcoal as long as the solution remains roughly the same and has an equally porous material to pass through. Demonstrate this concept by creating a crystal tree. Mix 6-tablespoons water, 6-tablespoons liquid bluing, 1-tablespoon ammonia and 6-tablespoons table salt in a glass beaker. Stir until the salt completely dissolves. Obtain heavy blotting paper, a highly absorbent paper often used for cosmetic purposes, and cut the paper in the shape of a tree. Color the tips of the paper tree with food coloring and let dry. Place the tree in a shallow tray and add two tablespoons of the solution around the tips of the tree. After several hours, crystals should form on the porous paper just as they formed on the charcoal.
  
  

Precautions

• Since the crystal growing solution includes ammonia, students must exercise extreme caution. Work in an area with good ventilation and never inhale ammonia fumes. Wear safety goggles to protect against splashes or eye irritation and wear gloves to help prevent the solution from touching your bare skin. Additionally, never store the crystal growing solution for too long since the solution decomposes into harmful cyanides.