sedimentary

Petrified Wood

Silicified wood (principally SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Brown, red, orange, and tan; Luster: Dull to waxy/vitreous; Structure: Microcrystalline quartz (Chalcedony/Jasper) preserving cellular wood structure; Cleavage: None; Specific Gravity: 2.6-2.9

Hardness: 6
Color: Brown, red, orange, and tan
Luster: Dull to waxy/vitreous

Identified May 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through permineralization where organic wood material is replaced by minerals, typically silica from volcanic ash, while buried under sediment. Processes often date back to the Triassic or Cenozoic periods.

Uses & applications

Used in high-end furniture (tabletops), lapidary work, jewelry (cabochons), and as museum or private collection display specimens.

Geological facts

Petrified wood is the state gemstone of Washington and Mississippi. It occurs when a tree is buried in an environment lacking oxygen, preventing aerobic decomposition and allowing minerals to seep in.

Field identification & locations

Identify by looking for bark textures and ring patterns on a material that feels significantly heavier than wood and is cold to the touch. Commonly found in Arizona (Petrified Forest National Park), Oregon, and Madagascar.