While there are many methods—ranging from the classic salt or sugar crystals to the vibrant "Magic Tree" cardboard kits—the gold standard for home growers is the . Alum (potassium aluminum sulfate) is a common pickling spice available at most grocery stores or pharmacies. It grows quickly, forms large, distinct geometric shapes, and is non-toxic.
As the water cools, it can no longer hold all that dissolved material. The excess "falls out" of the liquid and atoms begin to bond together in a repeating geometric pattern. This is the birth of a crystal. Method 1: The Fast and Easy Borax Crystal how to grow a crystal at home