How to Grow Alum Crystals

Alum crystals are among the easiest and quickest crystals you can grow. Simply mix 1/2 very hot tap water with 2-1/2 tablespoons of alum. You can get alum from the spice section of the grocery store or with canning and pickling supplies. The crystal growth becomes visible after a few minutes. You'll get thumbnail-size crystals in a matter of hours.

If you want to grow a large perfect crystal, choose one of the crystals and remove all of the others. You can add more solution to support the growth of this crystal.

Another interesting way to grow these crystals is to pour the alum solution over a small rock. You'll get a mass of "diamonds" on the stone. This is an easy project that produces a nice display.

Alum crystals are a good project for kids because you don't need boiling water, you're using a safe chemical and you get quick results. Be sure to let me know if you have any questions or need any help.