fossil

Petrified wood

Silicified wood, commonly quartz/chalcedony (SiO₂) replacing woody tissue

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, red, orange, and tan banding preserves wood grain. Typically vitreous to dull luster, microcrystalline quartz structure, and no prominent cleavage; specific gravity about 2.3–2.7.

Identified September 13, 2026More fossil →

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Physical properties

Formation & geological history

Fossilized wood formed when silica-rich groundwater replaced cell walls during burial, usually in volcanic-ash-rich sediments. Individual specimens range from Paleozoic to Cenozoic in age, commonly tens of millions of years old.

Uses & applications

Used as a decorative stone, lapidary material, paperweight, and collector specimen; polished sections are used for jewelry and display. It is generally less valuable than gem-grade agate.

Geological facts

The image shows strongly preserved longitudinal wood texture and iron-oxide red coloration, consistent with silicification and mineral staining. Some pieces may retain cellular structures visible under magnification.

Field identification & locations

Identify by recognizable bark or growth-grain patterns, quartz-like hardness, and inability to scratch with a steel knife; it should not fizz in dilute acid. Common sources include Arizona, Utah, Oregon, Indonesia, Madagascar, and Australia.