Petrified Wood is a fossil in which the organic remains have been replaced by minerals in the slow process of turning to stone. This petrification process generally results in a Quartz Chalcedony mineralization. Special rare conditions must be met in order for the fallen wood to be transformed into precious Fossil Wood or Petrified Wood. In general, the fallen trees get buried in an environment free of oxygen (anaerobic environment), which preserves the original tree structure and general appearance. The other conditions include a regular access to mineral rich water flowing through the wood, replacing the organic tree structure with inorganic stone. The end result is Petrified Wood, a tree, with its original basic structure in place, replaced by stone.
Elements such as manganese, iron, and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals take on a yellow, red, or another tint.
Following is a list of contaminating elements and related color hues:
carbon – black
cobalt – green/blue
chromium – green/blue
copper – green/blue
iron oxides – red, brown, and yellow
manganese – pink/orange
manganese oxides – blackish/yellow