fossil

Petrified Wood

Silicified Wood (Silicon Dioxide - SiO2)

Hardness: 6.5 to 7 on the Mohs scale. Color: Tan, brown, gray, greenish yellow, and reddish hues due to trace minerals. Luster: Dull to vitreous or waxy. Structure: Retains fibrous organic tree ring structures replaced by cryptocrystalline quartz (chalcedony/jasper). Specific gravity: ~2.6.

Hardness: 6
Luster: Dull to vitreous or waxy

Identified July 25, 2026More fossil →

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Physical properties

Formation & geological history

Formed when ancient plant material was buried under sediment or volcanic ash in an anaerobic environment. Groundwater rich in dissolved minerals (mainly silica) flows through the sediment, replacing original plant cells with minerals over millions of years (permineralization).

Uses & applications

Used for decorative lapidary work, bookends, table tops, polished display specimens, landscape architecture, and educational fossil collections.

Geological facts

Petrified wood preserves the original 3D cellular structure of ancient trees so precisely that tree species and growth rings can often be identified under a microscope. Entire petrified forests exist, such as the Petrified Forest National Park in Arizona.

Field identification & locations

Identified by wood grain texture, tree rings, and fibrous bark patterns combined with high rock-like hardness and density. Commonly found in ancient riverbeds, sedimentary basins, and volcanic ash deposits globally.

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