fossil

Petrified Wood

Silicified wood (primarily quartz, SiO2)

Hardness of 6.5 to 7 on the Mohs scale; colors include brown, tan, gray, red, and yellow due to mineral impurities like iron oxides; luster ranges from vitreous to dull; amorphous crystal structure at the macroscopic level with microcrystalline quartz (chalcedony/jasper) replacing original organic structures;…

Identified July 29, 2026More fossil →

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Physical properties

Formation & geological history

Formed when fallen trees are rapidly buried in sediment-rich environments lacking oxygen, preventing decay. Over millions of years, groundwater rich in dissolved silica flows through the organic material, replacing cellular wood structures with mineral deposits, usually quartz.

Uses & applications

Used for decorative carvings, lapidary art, high-end jewelry, custom countertops, bookends, and sought after by rockhounds and fossil collectors.

Geological facts

Petrified wood can preserve the cellular structure of ancient trees down to the microscopic level, sometimes allowing scientists to identify the exact extinct species of tree.

Field identification & locations

Can be identified in the field by its distinct wood-like grain, bark texture, and weight, which is significantly heavier than normal wood because it is composed of solid rock. Found worldwide in sedimentary rock layers associated with ancient floodplains and volcanic ash beds.

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