Petrified Wood, really is a fossil as well as a crystal. The chemical makeup of the wood has been replaced with another mineral over long expanses of time. This occurred during the Mesozoic Era and Paleozoic Eras. The minerals that replace the wood are often Agates or Chalcedony, and also quartz. Colors on each piece can range greatly.
The energy of petrified wood is ancient, it comes with a history of time, space & earth. Ancient energy has been contain in a once living being (tree). This is a piece of earth history unlike any other crystal.