sedimentary

Petrified Wood

Silicified Wood (SiO2)

AI-generated identification · may be incorrect

Hardness of 6.5 to 7 on the Mohs scale, vitreous to waxy luster, and maintains the original cellular structure of the tree. Colors vary widely from reds and browns to yellows and blacks due to mineral impurities.

Identified October 29, 2026More sedimentary →

Explore Petrified Wood in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed over millions of years when buried organic wood is slowly replaced by silica-rich groundwater in anoxic sedimentary environments. Commonly dates from the Triassic period onward.

Uses & applications

Used primarily in lapidary arts, decorative tabletops, jewelry making, and as sought-after museum or collector specimens.

Geological facts

Famous occurrences include the Petrified Forest National Park in Arizona, where entire ancient conifer forests turned completely to quartz. The replacement process can preserve microscopic cellular details of the original plant.

Field identification & locations

Identify by its distinct wood-like growth rings and bark texture coupled with a distinctly high weight and stone-like hardness. Found globally in ancient floodplains and volcanic ash beds.