How to Grow Alum Crystals

By eHow Hobbies, Games & Toys Editor

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Alum crystals form as attractive glasslike squares. Add different shades of food coloring and grow numerous crystals to make a colorful alum-crystal garden.

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Instructions

Difficulty: Easy

Things You’ll Need:

Nylon Threads
Glass Bowls
Glass Jars
Pencils
2 oz. alum or more

Step1

Heat 1/2 c. water almost to boiling.

Step2

Remove from heat.

Step3

Pour into a bowl.

Step4

Stir in alum slowly. Add in more until the alum is no longer dissolving but is starting to settle at the bottom of the bowl.

Step5

Pour a small amount of the solution into another bowl.

Step6

Allow to cool. Once cool, you should see small crystals forming.

Step7

Take out one of the crystals and allow it to dry completely. This is your "seed" crystal, or the place from which the rest of the crystal will grow.

Step8

Tie one end of a piece of thread around the crystal, and tie the other end around the middle of a pencil.

Step9

Prepare another solution, repeating steps 1 through 4.

Step10

Pour the solution into a glass jar.

Step11

Place the pencil over the jar so that the thread hangs down into the jar and the crystal is suspended in the solution.

Step12

Place a paper towel over the top of the jar to keep dust from getting into the crystals.

Step13

Allow several days for the crystal to grow.

Tips & Warnings

You can find alum in the grocery store, in the section for spices or canning.
Make sure to supersaturate your solution. This means continuing to add the alum and stir it in until the solution is saturated, and the alum begins collecting on the bottom of the dish.
If the thread hanging from the pencil is too long when you place it in the solution, just roll the pencil between your hands until the thread wraps around it and the length hanging down becomes shorter.

Comments

Anonymous said

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on 8/11/2006 When you are trying to add food coloring to the solution to color the crystals, don't directly put the food coloring into the solution because it will take up a lot of food coloring. I recommend that you first add food coloring to the alum, mix it to make sure that the tiny alum crystals are all colored. Let them dry, and then add them to the solution.They use this type of technique in crystal growing kits.

Anonymous said

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on 8/8/2006 Grow an Alum crystal, then burn the tip of the crystal. Next, you let it cool off. When the tip is black, then let it sit in ice cold water.

Anonymous said

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on 12/23/2005 For this you'll want something non-porous, like a glass tray, a glazed ceramic dish or a plastic saucer. Get a small bag of aquarium rocks at your local WalMart and select a handful of them. I recommend small, clear ones, but it's your choice.

Clean them in hot water, then dry with a paper towel. Spread these about in your dish and set aside.

Make a smaller alum and water solution as suggested; perhaps only a sixth or a fourth of it, depending on how large your dish is.

When the fluid is ready, carefully pour or ladle the liquid over the aquarium rocks. Set aside to dry.

Repeat this for the next few days, perhaps adding a few drops of color to the solution, and selectively pouring the liquid. In a few weeks, you'll have a rather interesting formation of crystals perfect for sitting in a window or as an attractive, and fun, centerpiece.

Remember not to let children try to eat the crystals!

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