An oak tree is in the genus Quercus. There are approximately 600 species of oaks.
It is from the Cenozoic Era in the Tertiary Period of the Miocene Epoch. It is about 5-15 million years old and comes the well known famous Stinking Water Creek area near Burns, Oregon.
These fossilized tree logs are found standing up right, because they were covered by an ash flow from volcanic activity, and sometimes the tree goes down 30-40 feet in the ground. Over the course of time the wood was replaced by cryptocrystalline quartz, largely chalcedony and jasper. During the replacement process by silica carried in underground waters, even the most minute details of the woody structure was preserved.
Petrified Wood in general is a stone of patience, and slow and steady growth. Petrified Wood can help one overcome limiting emotional patterns handed down through one's ancestors.