Petrified Wood Arizona Conifer Polished Rock. Lovely bookends from Petrified Conifer Tree Wood from Northern Arizona. These bookends are 5 inches high, 4 inches wide at the bottom and 1.5 inches thick. They are polished on front and left natural rough around the edges. They are covered with felt in the inside and on the bottom to protect you furniture. The Petrified Wood formed when a tree died and was buried by sediments. Minerals in the groundwater then permeated the wood, replacing the original organic matter and turning it to stone. The main mineral is silica, but trace elements in the silica create a variety of colors. Petrified Wood is a member of the Chalcedony family. It is very hard and takes an excellent polish. Northern Arizona is the home of the Petrified Wood Forest, a National Park since 1962. The park sprawls over 346 square miles and is one of the richest troves of the late Triassic Period fossils (210 million years old). It is considered one of the most important Petrified Wood areas in the world. Some logs as long as 213 feet have been found there! Metaphysical Properties: Petrified Wood is a stone of patience and slow and steady growth. Listing and template services provided by inkFrog.