sedimentary

Petrified Wood

Silicified wood (Quartz/Chalcedony/SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, cream, reddish; Luster: Waxy to dull (stony); Crystal structure: Microcrystalline (Cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9.

Hardness: 6
Color: Brown, tan, cream, reddish
Luster: Waxy to dull (stony)

Identified June 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through permineralization where organic wood material is replaced by minerals, typically silica (chalcedony or quartz), while retaining the original cellular structure. This specimen likely dates from the Triassic to the Cenozoic era, forming in sedimentary basins or volcanic ash beds.

Uses & applications

Used for ornamental decoration, jewelry (cabochons), lapidary art, and popular as geological collectibles.

Geological facts

Petrified wood is the state fossil of Washington and several other US states. The Petrified Forest National Park in Arizona is one of the world's most famous locations for these specimens.

Field identification & locations

Identify by looking for bark textures and growth rings preserved in stone. Found globally, especially in Arizona, Oregon, and Madagascar. Collectors look for high color contrast and preservation of wood grain detail.