Boil one cup of distilled water. Gradually stir in alum until no more will dissolve—you will see a thin layer of undissolved powder at the bottom. This is your supersaturated solution. Pour it carefully into the clean jar, avoiding any undissolved grains.
What you will witness is not magic but molecular geometry. The crystal grows not by adding random clumps but by repeating the same angles—because the internal arrangement of atoms dictates the external shape. A perfect cube of salt, a six-sided quartz point, the branching frost on a window: all obey the same hidden rules.
Dip your wooden skewer in water, roll it in dry sugar, and let it dry completely. These "seed crystals" give the new crystals a place to grip. Submerge the skewer in the syrup.
