Petrified wood is ancient wood transformed into stone. This fossil forms through permineralization, where organic wood is gradually replaced by minerals. It becomes buried by sediment, like volcanic ash or mud, protecting it from decay by limiting oxygen exposure.
Groundwater rich in dissolved minerals, primarily silica, then seeps into the buried wood. These minerals precipitate within the cellular structure and empty spaces, slowly replacing the original organic matter over millions of years. This process often preserves the wood’s original details, including growth rings and cellular patterns, creating a three-dimensional stone replica.
Natural Formation Environments
Petrified wood forms in specific geological settings where rapid burial and mineral-rich water converge. Ancient forests, particularly those near volcanic activity, are common sites for its formation. Volcanic ash, rich in silica, can quickly bury trees and provide the necessary minerals for permineralization.
River floodplains and deltas also serve as conducive environments, as trees can be rapidly buried by sediment carried by floodwaters. The lack of oxygen in these buried conditions inhibits decomposition, allowing the mineralization process to occur. Petrified wood is found globally, with notable occurrences including Arizona’s Petrified Forest National Park, the Yellowstone Petrified Forest, and vast areas in Argentina and Greece.
Collecting on Public and Private Lands
Understanding regulations for collecting petrified wood on different land types is important. On U.S. Bureau of Land Management (BLM) lands, hobby collecting is often permitted for personal, non-commercial use. Collectors can typically gather up to 25 pounds plus one piece per day, with an annual limit of 250 pounds per person. Pieces exceeding 250 pounds usually require a special permit, and commercial sale of collected wood from BLM land is prohibited without a contract.
Hand tools like shovels and picks are generally allowed, but motorized or heavy equipment and explosives are not. Certain BLM areas, such as wilderness areas or recreation sites, may have restricted or prohibited collecting.
The U.S. Forest Service (USFS) also allows limited personal collection on many national forest lands. Similar to BLM lands, collected material cannot be bartered or sold. Check with the local ranger district office for specific rules, as regulations vary by area.
In contrast, collecting petrified wood is generally prohibited in U.S. National Parks and National Monuments, with strict regulations and potential fines for removal. These protected areas prioritize the preservation of natural resources for all visitors.
State parks and state lands have varying rules; some may allow collection with specific permits or quantity limits, while others may prohibit it entirely. For collecting on private land, explicit permission from the landowner is always required, and obtaining written consent is a good practice. Responsible rockhounding ethics include minimizing environmental impact, filling any holes created, and respecting property boundaries.
Purchasing from Commercial Sources
Petrified wood is readily available through commercial channels for those who prefer not to collect or cannot access suitable locations. Rock and mineral shops frequently offer a selection of petrified wood specimens. Specialty fossil dealers often have more diverse and higher-quality pieces, catering to serious collectors.
Online marketplaces and dedicated fossil websites provide a broad array of options, allowing buyers to browse various shapes, sizes, and colors of petrified wood from around the world. Gem and mineral shows are also excellent venues to find petrified wood, offering opportunities to see pieces in person and speak with vendors.
Museum gift shops, particularly those near petrified forests, often sell ethically sourced pieces, supporting the park or museum. Available forms range from rough, natural pieces to polished slabs, decorative items, and jewelry.