sedimentary

Petrified Wood

Silicified Wood (SiO2)

AI-generated identification · may be incorrect

Hardness: 7.0 on Mohs scale. Color: Tan, white, gray, and brown. Luster: Vitreous to dull. Crystal structure: Amorphous to cryptocrystalline (chalcedony/quartz). Cleavage: None. Specific gravity: 2.6-2.9.

Hardness: 7
Color: Tan, white, gray, and brown
Luster: Vitreous to dull

Identified May 5, 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 through permineralization where organic wood materials are replaced by minerals (usually silica) from groundwater while retaining the original structure. Generally occurs in sedimentary environments like fluvial deposits.

Uses & applications

Commonly used for lapidary work, jewelry, decorative ornaments, furniture (table tops), and as highly sought-after display specimens for collectors.

Geological facts

The process converts the wood to stone over millions of years. Famous locations include the Petrified Forest National Park in Arizona, which contains logs from the Late Triassic Period (about 225 million years ago).

Field identification & locations

Identify by looking for bark textures, growth rings, and wood grain preserved in a heavy, stony material. Commonly found in erosion-prone badlands and ancient volcanic ash beds.