Welcome to Petrified Forest National Park
The trees arrived via major floods, only to be buried beneath silica-rich volcanic ash before they could decompose. Groundwater dissolved the silica, carried it through the logs and crystallized into solid, sparkly quartz mashed up with iron, carbon, manganese and other minerals. Uplift and erosion eventually exposed the logs. Souvenir hunters filched thousands of tons of petrified wood before Teddy Roosevelt made the forest a national monument in 1906 (it became a national park in 1962). Scavenge today and you'll be looking at fines and even jail time.