How to Make Rock Crystals

A crystal takes its distinctive shape and striking appearance from the rigid, repetitive arrangement of the atoms or molecules that make it up. This arrangement often occurs when a fluid containing suitable material evaporates or becomes a solid, a process known as crystallization. Many kinds of crystals are abundant in nature, but it is also easy and fun to make your own rock crystals at home, using common ingredients and simple techniques.

Things You'll Need

• Cooking pot or teakettle
• Water
• Glass jar
• Spoon
• Measuring cup
• String
• Scissors
• Pencil
• Sugar, table salt, Epsom salts and/or baking soda
• Paper clip (optional)

Instructions

1. Heat the water. Using a pot or teakettle, heat 2 cups of water. Be sure to get the water very hot or boiling, but take care to avoid spills or burns.

2. Add dry material. Use a spoon to stir sugar, table salt, Epsom salts or baking soda into the hot water until no more will dissolve. If you want to use the entire 2 cups of water for one batch of crystals, you probably will be able to dissolve 4 cups of sugar, 1 and 2/3 cups of salt or Epsom salts, or 1/4 cup of baking soda. When no more material will dissolve, you have a saturated solution. This step may take a while, but dissolving more material can lead to better crystals.

3. Pour the solution into a glass jar.

4. Place the string. Cut a piece of string about 12 inches long. Tie one end to the middle of a pencil. Place the pencil across the mouth of the jar so the string dangles into the solution but does not touch the bottom. If the string is too long, you can trim it to fit or wrap it around the pencil.

5. Store the jar. Place the uncovered jar (with pencil and string) in a stable, secure place where it isn't likely to be disturbed.

6. Wait and watch. Over the course of several days, the water will evaporate, and crystals will form on the string. This process can take a week or longer, but the results should be well worth the wait.

Tips & Warnings

• Add a few drops of food coloring to your solution in step 2 to create colorful crystals. You can use sugar in step 2 to make homemade rock candy. For a special treat, add a few drops of flavor extract. To give your crystals an extra boost, remove the string after step 4, lay it on a plate and allow it to dry for a day or so. You should see tiny "seed crystals" begin to form. You can then place the string (crystals and all) back into the jar of solution and proceed to step 5. Instead of a jar and string, you can pour your solution into disposable cups or shallow bowls. As the water evaporates, crystals will form on the surface of the cup or bowl. To make your string hang straight, you can tie a paper clip to the end to weigh it down.

• Be very careful with the hot water, and be sure to choose utensils and containers that are safe for use with hot or boiling water.

References

• The Field Museum
• Growing Crystals
• The Science of Candy

Resources

• Crystal