fossil

Petrified Wood

Silicified wood (primarily SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, cream, gray; Luster: Waxy to dull; Structure: Preserves original plant grain and cellular structure; Cleavage: None/Conchoidal fracture.

Hardness: 6
Color: Brown, tan, cream, gray
Luster: Waxy to dull

Identified July 17, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, cream, gray; Luster: Waxy to dull; Structure: Preserves original plant grain and cellular structure; Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed through permineralization where organic wood materials are replaced by minerals (usually silica/quartz) from groundwater while buried in sediment or volcanic ash. Common in Mesozoic and Cenozoic eras.

Uses & applications

Used for ornamental carvings, jewelry (cabochons), furniture making, and as a popular lapidary and collector's specimen.

Geological facts

Petrified wood is the state fossil of Arizona. The process of petrification occurs underground without oxygen, preventing aerobic decomposition and allowing minerals to take the shape of the wood grain.

Field identification & locations

Identify by looking for distinct bark-like textures, growth rings, or wood grain patterns that have a heavy, stone-like feel. Commonly found in areas with past volcanic activity near ancient forests.