sedimentary

Petrified Wood

Silicified Wood (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7.0 (Mohs scale), Color: Brown, grey, tan, and creamy white, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline quartz), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.9

Hardness: 6

Identified May 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via permineralization where organic remains are replaced by minerals (usually silica) while retaining original structure. This specimen likely dates from the Paleozoic to Cenozoic eras, formed in low-oxygen environments like river deltas or volcanic ash falls.

Uses & applications

Commonly used for decorative ornaments, lapidary work (cabochons), jewelry, and as educational fossils for collectors. Small tumbled stones are popular in metaphysical and hobbyist markets.

Geological facts

Petrified wood is the state fossil of Arizona. The cell-by-cell replacement by minerals is so precise that it can often preserve details of the original tree's bark and internal growth rings.

Field identification & locations

Identify by looking for preserved wood patterns, wood-like grain, and growth rings in a stony material. Commonly found in areas with historical volcanic activity or sedimentary basins like the Petrified Forest National Park in Arizona, USA.