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How to Make a Silica Garden

Silica is a mineral; sodium silicate works well for crystal-growing experiments. Crystal-growing projects, called silica gardens or more commonly, chemical gardens, offer the means to learn about how crystals develop. Different chemicals produce different colors and forms when added to a dissolved solution of sodium silicate. Make a silica garden to watch the growth patterns and create your own display of color and forms.

Things You'll Need

Beaker, or heat-resistant glass, such as a measuring cup
Burner, such as a Bunsen burner or gas ring
Pot holder or oven mitt
Clear glass container, such as a Mason jar or small fishbowl
Sodium silicate
Nickel chloride (optional)
Cobalt chloride (optional)
Iron sulfate (optional)
Glass rod
Tweezers
Cling film or lid for the container
Tape

Instructions

- 1
  Bring 2 cups of water to boil in a beaker. Stay with the beaker. If it boils dry, the glass could shatter.
- 2
  Keep the water on the burner. Stir in 6 to 8 rounded teaspoonfuls of sodium silicate. This dense white powder takes a long time to dissolve, so keep stirring.
- 3
  Turn off the burner. Leave the sodium silicate mixture cooling as you prepare the container for the silica garden.
- 4
  Deposit a rounded teaspoon full of each mineral in the bottom of a clear container. Place the minerals at least one inch from each other, within one inch of the glass. Minerals will climb the glass, creating a colorful display. For example, use nickel chloride, cobalt chloride and iron sulfate to make a green, blue and black silica garden.
- 5
  Hold a glass rod inside the container and carefully pour the sodium silicate mixture down the rod, using an oven mitt or pot holder to handle the beaker. Using the rod to guide the liquid helps to prevent the mixture from disturbing the piles of chemicals.
- 6
  Leave the container in place and take care not to disturb it by moving or jostling it as the crystals grow. It can take about two hours for the crystals to fully develop.
- 7
  Cover the container with cling film, the type of plastic wrap that forms a seal when you stretch it, or a lid. Use tape to seal it securely. This will help to preserve your silica garden.

Rocks & Minerals