fossil

Petrified Wood

Silicified Wood (SiO2 permineralization)

Hardness: 6.5-7 (Mohs scale), Color: tan, brown, beige, Luster: dull to waxy, Crystal Structure: Cryptocrystalline quartz (chalcedony), preserves organic wood textures and grain patterns. Specific gravity: 2.6-2.9.

Hardness: 6

Identified July 17, 2026More fossil →

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Physical properties

Formation & geological history

Formed during the permineralization process where organic material is replaced by minerals, typically silica (quartz/chalcedony), in the absence of oxygen. Often found in sedimentary layers dating from the Devonian to the Holocene.

Uses & applications

Ornamental carving, jewelry (cabochons), interior design (tabletops/bookends), and as an educational geological specimen for fossil collectors.

Geological facts

Unlike many fossils which are impressions, petrified wood is a three-dimensional replacement of the original plant tissue. It can preserve individual cell structures and growth rings of prehistoric trees.

Field identification & locations

Identify by looking for wood-like grain, bark patterns, or rings that have been transmuted into hard, stony material. It will not scratch with a steel knife. Commonly found in areas with ancient volcanic ash or river delta deposits.

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