sedimentary

Petrified Wood

Silicified Wood (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Brown, tan, and dark grey. Luster: Dull to waxy. Crystal structure: Microcrystalline quartz (chalcedony/opal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Brown, tan, and dark grey
Luster: Dull to waxy

Identified June 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formation through permineralization where organic wood materials are replaced by minerals (usually silica) in anaerobic conditions under sediment. This often occurred millions of years ago in volcanic or fluvial environments.

Uses & applications

Ornamental jewelry, lapidary art, decorative bookends, and popular geological collecting specimens. Large slabs are used for furniture.

Geological facts

Unlike typical fossils, petrified wood is a three-dimensional representation of the original organic material. Some specimens retain perfectly visible tree rings and bark textures.

Field identification & locations

Identify by looking for wood-like grain patterns, bark textures, or growth rings in a heavy, stony material. Commonly found in areas with high ancient volcanic activity or arid badlands.