sedimentary

Petrified Wood

Silicified Wood (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Tan, brown, and grey with possible reddish hints; Luster: Waxy to vitreous; Crystal structure: Usually cryptocrystalline (microscopic quartz); Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Tan, brown, and grey with possible reddish hints
Luster: Waxy to vitreous

Identified May 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the process of permineralization where organic wood materials are replaced by minerals (usually silica) over millions of years, typically in volcanic ash or river sedimentary environments from the Triassic through Cenozoic eras.

Uses & applications

Used for jewelry (cabochons), interior decoration (tables, bookends), and highly sought after by geological collectors.

Geological facts

Arizona's Petrified Forest National Park contains one of the world's largest and most colorful concentrations of petrified wood. It is essentially a fossil that has turned completely to stone.

Field identification & locations

Identify in the field by looking for cellular wood structures, growth rings, or bark textures preserved in stone. Found globally in areas with ancient fossilized forests like the USA, Argentina, and Egypt.