There are many types of homemade crystals you can make by combining water and mineral compounds. One easy crystal that can be made at home is an alum crystal, which is known for its large size. To make an alum crystal, you need water, alum, nylon fishing line, a popsicle stick, two clean jars, a spoon and paper towels. Create a supersaturated solution of alum in water to create a seed crystal, then dangle this crystal on a line into solution to allow more layers to form around it.
- Pour water into a jar
Pour 1/2 cup of hot water into one of the clean jars.
- Add alum to the water
As you add the alum, stir slowly. Pour the alum carefully into the water until the alum stops dissolving. You want enough to completely saturate the water.
- Cover the jar
Use a paper towel to loosely cover the jar, and let the solution sit overnight. The paper towel prevents dust from getting into the mixture.
- Transfer the alum crystals into the other jar
When the solution is poured into the other jar, you should see small crystals at the bottom of the original jar.
- Select the best crystal
After you have found the largest and best-shaped crystal of the batch, tie a nylon fishing line around it. Secure the other end to a popsicle stick. Ideally, the crystal should hang from the stick into the jar with enough length so the crystal is fully immersed in the solution but is not touching the bottom or sides of the jar.
- Continue to grow your crystal
Remove any other crystals from the jar, and cover the jar with a paper towel. Your crystal will continue to grow while it is immersed in the solution. If any other crystals begin to form on the sides or bottom of the glass, remove your crystal from the jar, and pour the solution into a clean jar. Place your crystal in the new jar, and cover it.