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How to Grow Opal from Sodium Silicate

Opal is classified as one of six precious gemstones found in nature. Composed of silica and water, this non-crystalline gem is formed through the solidification of gelatinous or liquid silica deposited in rock cavities and cracks. The liquid silica is created from decaying vegetation, wood, bones or crustaceans. By combining a few simple ingredients, you can create your own opal by replicating the initial stage of its growth. Just remember that what you'll get is a crude opal, not a precious one.

Things You'll Need

½ cup sodium silicate (water glass)
½ cup household vinegar
Disposable clear-plastic container
Disposable spoon
Black sheet of paper

Instructions

- 1
  Purchase sodium silicate, which is also known as water glass, from your local hardware store. You will also need household vinegar, a disposable spoon and a disposable clear-plastic container.
- 2
  Combine ½ cup of sodium silicate and ½ cup of vinegar in a disposable clear-plastic container. Mix using a disposable spoon. Sodium silicate is a gel, so be sure to thoroughly mix the sodium silicate and the vinegar.
- 3
  Place the plastic container with the sodium silicate and the vinegar in a stable, secure location at room temperature. Do not move or disturb the container for several hours, or leave it overnight to ensure that the mixture has enough time to dry completely. The mixture is dry when it has become a hardened gel that is semi-clear to clear. This hardened gel is one large opal.
- 4
  Put the container with the hardened opal gel on top of a black sheet of paper. This will allow you to see the cracks and small details that represent how opal begins to form in nature. These details also point up the differences between common, cracked opals and smooth, precious opals sold in jewelry stores.

Rocks & Minerals