fossil

Petrified Wood

Fossilized Wood (SiO2 replacing organic matter)

Hardness: 6.5-7 on Mohs scale. Color: Tan, beige, brown, or grayish-brown. Luster: Dull to waxy or vitreous. Structure: Preserves fibrous cellular wood grain structure. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.6-2.65.

Hardness: 6
Color: Tan, beige, brown, or grayish-brown
Luster: Dull to waxy or vitreous

Identified July 25, 2026More fossil →

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Physical properties

Formation & geological history

Formed through permineralization, where organic wood material is buried under sediment or volcanic ash and gradually replaced by silica-rich minerals (like chalcedony or quartz) over millions of years, often dating back to the Triassic or Jurassic periods.

Uses & applications

Used primarily in lapidary work, ornamental carvings, polished display specimens, jewelry, bookends, and educational collections.

Geological facts

Petrified wood can retain cellular detail down to the microscopic level, allowing paleobotanists to identify the exact tree species that lived tens or hundreds of millions of years ago.

Field identification & locations

Identified in the field by its distinctive tree bark or wood grain texture combined with rock-like weight and quartz-level hardness. Commonly found in sedimentary deposits, riverbeds, and fossiliferous beds worldwide (e.g., Arizona, USA; Madagascar; Indonesia).

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