Rock Identifier
Petrified Wood (Silicified wood (primarily quartz, SiO2)) — fossil
fossil

Petrified Wood

Silicified wood (primarily quartz, SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale; colors range from brown, tan, and grey to red and yellow due to mineral impurities; vitreous to waxy luster; cryptocrystalline quartz structure; specific gravity around 2.5-2.7.

Identified More fossil →
Explore Petrified Wood in the encyclopedia →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Hardness of 7 on the Mohs scale; colors range from brown, tan, and grey to red and yellow due to mineral impurities; vitreous to waxy luster; cryptocrystalline quartz structure; specific gravity around 2.5-2.7.

Formation & geological history

Formed when organic plant material is buried in an oxygen-depleted environment under sediment and slowly replaced by minerals (usually silica) over millions of years, often dating from the Triassic period or younger.

Uses & applications

Used for lapidary work, making decorative objects, jewelry, bookends, furniture tops, and as collector specimens.

Geological facts

Petrified wood can preserve the original cellular structure of the tree down to microscopic details. The Petrified Forest National Park in Arizona is one of the most famous localities in the world for these fossils.

Field identification & locations

Identify by observing typical wood grain and bark textures combined with stone-like weight, coldness, and hardness that can scratch glass. Found worldwide in sedimentary rock layers associated with ancient river floodplains and volcanic ash deposits.

More like this

Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

fossil
Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

fossil
Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil
Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Rounded sedimentary pebble (Likely micritic limestone or calcareous sandstone) — sedimentary

Rounded sedimentary pebble

Likely micritic limestone or calcareous sandstone

sedimentary
Chert with Fossil Brachiopod (Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion) — sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary