fossil

Petrified Wood

Silicified Wood (SiO2 permineralization)

Mohs hardness: 6.5-7. Colors: brown, tan, reddish-orange, and grey due to iron/manganese impurities. Luster: dull to waxy. Structure: preserves the original cellular structure of wood. Specific gravity: 2.6-2.9.

Hardness: 6
Luster: dull to waxy

Identified July 1, 2026More fossil →

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Physical properties

Formation & geological history

Forms when woody debris is buried in sediment or volcanic ash and undergoes permineralization, where minerals like silica replace the organic matter over millions of years (commonly Triassic to Cretaceous ages).

Uses & applications

Used for decorative items, jewelry (cabochons), interior design (tables, bookends), and as educational fossil specimens for collectors.

Geological facts

The process can preserve the microscopic details of tree rings and bark patterns so accurately that the original species can often be identified by paleobotanists.

Field identification & locations

Identify by looking for wood-grain patterns, bark features, or growth rings on a stone that is much heavier and harder than actual wood. Common in areas like Arizona (USA), Madagascar, and Indonesia.

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