How to Make Your Own Alum Crystals


Creating crystals out of alum powder is an easy process that can be completed using materials from home and the grocery store. It can teach children about science, or can be used to create decorations, paperweights, or garden decorations. It will take about three weeks to make your own alum crystals.

    Add 4 oz. of alum powder to 2 cups of water over a medium flame. Stir until all alum is dissolved, and add another 4 oz. Continue adding and stirring until the powder no longer dissolves. The water is now saturated with alum.

    Remove the mixture from heat, and let it cool. Pour half of the mixture into the shallow dish and leave uncovered. Pour the other half into a glass jar and stir in an additional tablespoon of powder. Cover with a cloth and leave in a consistently warm location.

    Collect the crystals that form in the dish once the water has dissolved. This may take several days. Tie one end of the string around the stick and the other end around the largest harvested crystal.

    Set the stick on top of the jar so that the crystal hanging from the string is suspended in the mixture. Replace the jar in the previous warm location.

    Remove the crystal from the solution after about two weeks, when it should be completely formed. Repeat this process for the remainder of the crystals in the dish, if desired. Typically, 5 to 10 small crystals will appear in the dish. However, one of these small crystals will spawn dozens of larger alum crystals in the jar.

    Things You'll Need

    • Pot
    • Alum powder
    • Shallow dish
    • Glass jar
    • Cloth
    • String
    • Stick


    • Alum powder can be found at local drug stores or ordered online.

      By explaining each step of the process and researching the chemical reactions that take place, even children without a passion for science will be interested and educated.

      This is an easy experiment to use for a science fair project. The child can complete each step alone, as well as understand everything that happens.


    • Do not inhale or ingest alum powder. It is mildly toxic, and can irritate skin and mucous membranes.

About the Author

Willow Sidhe is a freelance writer living in the beautiful Hot Springs, AR. She is a certified aromatherapist with a background in herbalism. She has extensive experience gardening, with a specialty in indoor plants and herbs. Sidhe's work has been published on numerous Web sites, including

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