fossil

Petrified Wood

Silicified Wood (Permineralized Lycopsid, Conifer, or Hardwood)

Hardness: 6.5-7 (Mohs scale), Color: Brown, gray, black, and white streaks, Luster: Dull to waxy, Structure: Cryptocrystalline quartz preserving cellular plant structure, Specific Gravity: 2.6-2.9

Hardness: 6

Identified July 14, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Brown, gray, black, and white streaks, Luster: Dull to waxy, Structure: Cryptocrystalline quartz preserving cellular plant structure, Specific Gravity: 2.6-2.9

Formation & geological history

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

Uses & applications

Used for decorative items, jewelry (cabochons), lapidary art, furniture (tabletops), and as scientific/educational specimens.

Geological facts

Depending on the minerals present during fossilization, petrified wood can turn various colors: iron produces reds and yellows, while manganese produces pinks or blacks. Entire forests, such as the Petrified Forest National Park in Arizona, have been preserved this way.

Field identification & locations

Identify by looking for bark-like exterior textures and internal growth rings. It will feel much heavier and colder than wood and cannot be scratched by a steel knife. Common in volcanic regions and sedimentary basins.

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