sedimentary

Petrified Wood

Silicified wood (Quartz/Chalcedony/Opal)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish-pink, grey; Luster: Vitreous to waxy; Structure: Retains cellular structure of original wood; Cleavage: None (conchoidal fracture); Gravity: 2.6-2.9

Hardness: 6
Color: Brown, tan, reddish-pink, grey
Luster: Vitreous to waxy

Identified June 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through permineralization where organic wood materials are replaced by minerals (usually silica) in anaerobic conditions, often under volcanic ash or sediment layers. Most specimens are 20 to 200 million years old.

Uses & applications

Used for ornamental furniture, jewelry (cabochons), lapidary art, aquarium decor, and high-value geological collections.

Geological facts

The word 'petrified' comes from the Greek root 'petro,' meaning rock. Entire forests, like the one in Arizona (Petrified Forest National Park), have been preserved this way since the Triassic period.

Field identification & locations

Identify by visible bark-like textures or growth rings combined with the weight and hardness of stone. Found in various global locations including the USA, Argentina, Egypt, and Indonesia.