Petrified Forest National Park's Crown Jewel: Petrified Wood

The special treasure of Arizona's Petrified Forest National Park is its unparalleled concentration of petrified wood—specifically, the Late Triassic (225–207 Ma) Araucarioxylon, Woodworthia, and Schilderia logs exposed in the Chinle Formation.

How It Formed

1. Trees (conifer-like, up to 200 ft tall) fell in floodplains.
2. Buried rapidly by volcanic ash/silt → anaerobic.
3. Groundwater rich in dissolved silica (from volcanic ash) permeated wood.
4. Silica (quartz) precipitated in cell structure, replacing organic material atom-by-atom (permineralization).
5. Trace minerals (Fe, Mn, Cr) created rainbow colors: red, yellow, purple, blue, white.

Key Sites

• Crystal Forest: Dense concentration of brilliant logs.
• Rainbow Forest: Most colorful; museum + Giant Logs trail.
• Jasper Forest: Scenic vistas, less visited.
• Black Forest: Dark, hematite-stained logs.

Beyond Wood

Park also preserves: Petroglyphs (Ancestral Puebloan), Agate House (pueblo ruin), Fossil clams, amphibians, phytosaurs, early dinosaurs (e.g., Chindesaurus), and Painted Desert badlands.

Collecting petrified wood is prohibited (federal law); $325M+ in stolen wood estimated. The park protects one of Earth's best fossilized forest records.