fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Hardness 6.5-7 on Mohs scale; color ranges from yellow-brown, tan, to deep dark brown; dull to vitreous or waxy luster; retains preserved fibrous wood grain structure; no cleavage; fracture is conchoidal to splintery.

Identified July 26, 2026More fossil →

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Physical properties

Formation & geological history

Formed when fallen trees are buried rapidly under sediment or volcanic ash, saturated with mineral-rich groundwater. Over millions of years, silica replaces the organic cellular matter through permineralization, preserving internal structures.

Uses & applications

Used extensively in lapidary arts, decorative displays, carved ornaments, cabochons, tabletop manufacturing, and as popular fossil collection specimens.

Geological facts

Some petrified wood specimens preserve cellular structures so perfectly that individual tree rings and cell walls can be identified under a microscope. Entire petrified forests exist worldwide, such as the Petrified Forest National Park in Arizona.

Field identification & locations

Look for distinct wood grain patterns, tree ring structures, or bark textures combined with the weight and hardness of stone or chalcedony. Common in sedimentary beds, volcanic deposits, and river gravels.