What is Petrified Wood? 🪵 💎 Petrified Wood is a type of fossil that formed from ancient trees. While most people think the tree “turned to stone”, what actually happened is the tree underwent a fossilization process called petrificiation or permineralization, replacing the organic material of the tree with minerals. When a tree falls and is rapidly buried by river sediments or volcanic ash, it creates a reduced oxygen environment (anaerobic). This low-oxygen environment causes the decay proces