Rock Identifier
Petrified wood (Silicified fossil wood; commonly quartz (SiO₂) replacing or filling wood tissues) — fossil
fossil

Petrified wood

Silicified fossil wood; commonly quartz (SiO₂) replacing or filling wood tissues

AI-generated identification · may be incorrect

Brown and tan, irregular wood-like texture with possible preserved grain; typically Mohs 6.5–7, vitreous to dull luster, no cleavage, and microcrystalline quartz structure. The photo alone does not confirm the identification; a weathered concretion or other fossil could look similar.

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Physical properties

Brown and tan, irregular wood-like texture with possible preserved grain; typically Mohs 6.5–7, vitreous to dull luster, no cleavage, and microcrystalline quartz structure. The photo alone does not confirm the identification; a weathered concretion or other fossil could look similar.

Formation & geological history

Forms when buried wood is gradually mineralized by silica-rich groundwater, preserving its structure; fossilization may occur over geological timescales, often millions of years. Found in sedimentary deposits and volcanic ash beds.

Uses & applications

Collected as a fossil and used for carvings, ornaments, and polished lapidary pieces; larger attractive pieces can be cut for display.

Geological facts

Petrified wood can preserve growth rings and cellular details, and some specimens show striking mineral colors from iron or other impurities.

Field identification & locations

Look for consistent grain, rings, or cellular patterns throughout a freshly exposed surface, rather than just a wood-like outer shape. Notable deposits occur in Arizona, the western United States, and many other regions.

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