fossil

Fossilized wood (petrified wood)

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing wood tissue

AI-generated identification · may be incorrect

Typically hardness 6.5–7, gray, brown, tan, or black coloration, and waxy to glassy luster; original growth rings or fibrous wood texture may remain, with no obvious cleavage. The pictured piece appears polished or naturally weathered and contains dark silicified zones with iron-oxide staining.

Identified August 13, 2026More fossil →

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Physical properties

Formation & geological history

Buried wood was preserved as groundwater gradually replaced cell walls with silica, often during volcanic-ash-rich burial; ages range from tens of thousands to hundreds of millions of years. Exact age and locality cannot be determined from the image.

Uses & applications

Used as a lapidary material for cabochons, slabs, carvings, bookends, and decorative specimens; valuable pieces display vivid color, intact grain, and contrast.

Geological facts

Petrified wood is a fossil, not technically a rock type, though it is rock-like and commonly dominated by quartz or chalcedony.

Field identification & locations

Identify it by visible wood grain, growth rings, cellular texture, and quartz-like hardness; common deposits occur in the western United States, Madagascar, Indonesia, and Australia. A steel file should not easily scratch silica-rich material.