The change that takes place on the base foundation rock material put into a coal or depression garden, as they used to be called, is a chemical reaction between the base material and the reactant.
The reactant that causes the crystals to grow is the ammonia that is put into the liquid holding the rock being used.
How to Grow Crystals on a Rock Garden
* If working with more than one type of rock, label the bowls.
* Cluster the charcoal briquettes or stones in the center of the bowl.
* In this order, mix 4 to 6 tablespoons of table salt, 4 to 6 tablespoons of liquid laundry bluing, 4 to 6 tablespoons of water, and one tablespoon of ammonia. Make a separate batch for each garden being grown.
* Gently stir the mixture but don’t be concerned it the salt doesn’t dissolve completely.
* Spoon the mixture over the rocks. Option: save a few spoonfuls of mixture to add to the bottom of the bowl over the next few days and extend the crystal growing process.
* Drop food coloring over the coated stones. More than one color can be used for each crystal garden.
* Crystals should begin to form in twenty or thirty minutes. They will continue to grow for a day or two. If extra growing liquid was held aside, add to the bottom of the bowl at this point.