sedimentary

Petrified Wood (Agatized/Silicified Wood)

Silicified Wood / Chalcedony (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Tan, cream, or brown with visible wood-grain patterns; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline (Microcrystalline Quartz); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.9

Hardness: 6
Color: Tan, cream, or brown with visible wood-grain patterns
Luster: Waxy to vitreous

Identified March 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via permineralization, where organic wood material is replaced by minerals (usually silica) from groundwater while buried in sediment. This process typically occurs over millions of years, often in volcanic ash beds or river floodplains (Triassic to Neogene periods).

Uses & applications

Used in lapidary arts for jewelry, bookends, and decorative furniture. Highly valued as museum-quality display specimens and for teaching paleobotany.

Geological facts

The specimen displays distinctive cellular structural preservation, often called 'agatized' or 'opalized' wood depending on the mineral replacement. The Petrified Forest National Park in Arizona is one of the world's most famous locations for these specimens.

Field identification & locations

Identify in the field by looking for 'bark-like' exterior textures and внутренней wood-grain patterns that remain despite the object being heavy and cold like stone. Found frequently in eroded badlands and gravel pits in the Western United States (Arizona, Oregon, Washington).