Rock Identifier
Petrified Wood (Silicified wood (SiO2)) — fossil
fossil

Petrified Wood

Silicified wood (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, waxy to vitreous luster, amorphous crystal structure, and conchoidal fracture. Displays earthy brown, yellow, and tan wood-grain patterns.

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Physical properties

Hardness of 7 on the Mohs scale, waxy to vitreous luster, amorphous crystal structure, and conchoidal fracture. Displays earthy brown, yellow, and tan wood-grain patterns.

Formation & geological history

Formed over millions of years through permineralization, where organic wood tissue is completely replaced by silica minerals like quartz or chalcedony in anoxic sedimentary environments.

Uses & applications

Used for ornamental carvings, decorative lapidary items, jewelry, and prized by fossil collectors.

Geological facts

Famous occurrences include the Petrified Forest National Park in Arizona, featuring logs dating back over 200 million years to the Triassic period.

Field identification & locations

Identified in the field by retaining original wood cellular structures alongside a distinctly high rock hardness and glassy fracture. Found globally in sedimentary strata associated with ancient volcanic ash beds.

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