fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Hardness: 6.5-7 (Mohs scale), Color: tan, brown, yellowish-grey, Luster: dull to earthy, Structure: preserves original organic cellular structure, Specific Gravity: 2.6-2.9

Hardness: 6

Identified July 6, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: tan, brown, yellowish-grey, Luster: dull to earthy, Structure: preserves original organic cellular structure, Specific Gravity: 2.6-2.9

Formation & geological history

Formed via permineralization where organic material is replaced by minerals, typically silica, over millions of years after burial in sediment or volcanic ash. Common in Mesozoic era deposits.

Uses & applications

Ornamental use, decorative lapidary work, educational specimens, and jewelry (cabochons).

Geological facts

The process of petrifaction must occur in an anaerobic environment to prevent decay. Famous sites include the Petrified Forest National Park in Arizona, USA.

Field identification & locations

Identified by the preservation of wood grain, bark textures, or tree rings in a heavy, stony material. Found in sedimentary basins globally where ancient forests were buried.