How To Make Crystals

Growing a crystal garden is a lot of fun! This science project is easy to make at home using common household equipment along with alum powder, found at educational or science stores or online.

Step 1

Ingredients and supplies:

  • 5-6 ounces alum powder
  • 2 cups water
  • Food coloring (optional)
  • Glass Jar
  • Saucepan
  • Wooden spoon
  • Shallow dish, like a pie pan
  • Cloth
  • String
  • Pencil or stick

Step 2

Set up the crystal growing area. Find an area in your home that is warm and will not be disturbed when you leave your crystals to grow there for a few days.

Step 3

Heat the alum powder. Mix 4 ounces of alum powder with 2 cups of water in your saucepan. Heat over medium-low, stirring constantly, until the alum powder is fully dissolved. Add a little more powder until it stops dissolving in the water. This is very important in order for crystals to grow. Add a few drops of food coloring if you want to change the color of the crystals.

Step 4

Prepare the solution for crystals to grow. Let the alum solition cool until you can handle it safely. Then pour part of the solution into the shallow dish, and the rest into a glass jar. Stir in another tablespoon of alum powder into the solution in the jar. Then cover the jar with a cloth, and set it aside. Do not cover the shallow dish. Place both in your crystal growing area, and do not disturb them.

Step 5

Wait. Now, wait for crystals to grow. Be patient, because this should take several days. Once the solution has completely evaporated from the shallow dish, you will have several crystals left in the bottom. Select the biggest crystal; this will form the base for the rest of your alum crystals using the alum mixture in the jar.

Step 6

Prepare the crystal growing mixture. Tie a piece of string around the crystal that you have selected. With the other end tied around a pencil or stick, suspend it in the solution in the glass jar. Try not to tie it so that the crystal or string touches the side or bottom of the jar. Now move the jar with the alum solution back to your crystal growing area. Do not cover it with the cloth.

Step 7

Watch the crystals grow. It will take up to 2 weeks for the crystals to fully grow in the solution. After two weeks, you can remove the crystal from the solution and enjoy it.

Growing alum crystals takes some patience, but it is a fun and interesting project. The crystals form because as the liquid cools, it is no longer able to hold as much alum as when the mixture was warm. You can use the same process to make salt crystals, or even edible sugar crystals. Do not eat alum or salt crystals.


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