fossil

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of Cellulose)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Tan, brown, beige, and white; Luster: Vitreous to waxy (when polished); Structure: Cryptocrystalline quartz preserving original organic cellular structure.

Hardness: 6
Color: Tan, brown, beige, and white
Luster: Vitreous to waxy (when polished)

Identified July 6, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Tan, brown, beige, and white; Luster: Vitreous to waxy (when polished); Structure: Cryptocrystalline quartz preserving original organic cellular structure.

Formation & geological history

Formed through permineralization over millions of years (often Mesozoic or Cenozoic eras) where organic wood material is replaced by silica-rich groundwater while buried under volcanic ash or sediment.

Uses & applications

Used primarily for ornamental purposes, lapidary art, jewelry, home decor (bookends, tabletops), and as geological collection specimens.

Geological facts

Petrified wood is the state stone of Washington and Arizona. The processes preserve such fine detail that even tree rings and individual bark cells can often be observed under a microscope.

Field identification & locations

Identify in the field by looking for faint wood-grain patterns, knots, or bark-like textures in a stone that feels heavy and cold like quartz. Common in Arizona, Oregon, and Washington.