fossil

Petrified Wood

Silicified Wood (SiO2)

Hardness of 7 on the Mohs scale, colors ranging from brown and grey to multicolored hues, vitreous to waxy luster, amorphous crystal structure (quartz/chalcedony replacing organic material), no true cleavage, specific gravity of 2.5-2.7.

Identified August 3, 2026More fossil →

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Physical properties

Formation & geological history

Formed when plant material is buried in an oxygen-free environment under sediment, preventing decay, and groundwater rich in dissolved silicas flows through, replacing the original organic cells with minerals over millions of years.

Uses & applications

Used for decorative objects, lapidary art, jewelry, furniture accents, and as collector specimens.

Geological facts

Petrified wood can preserve microscopic cellular structures of ancient trees, allowing scientists to identify species that lived millions of years ago.

Field identification & locations

Identified by its distinctly wood-like grain and exterior texture combined with a stone-like weight, hardness, and cold feel. Found worldwide, notably in regions like Arizona's Petrified Forest National Park.