Petrified Wood is formed by the replacement of the wood by siliceous material. Ancient forests which became immersed in water containing silicas are the basis of petrified wood. Scientist can still not adequately explain the process. The final product looks like wood but it actually is a stone. The decaying cells of the wood were replaced by the silica and, because each growth ring in any particular tree varies in hardness, decay seems to have taken place at varying rates. The replacement by the silica has been at different times with the result that the wood opal has different colors showing in the same stone. Many people are amazed when they see it.
