mineral

Petrified Wood

Silicified Wood (primarily Quartz/SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Brown, gray, tan, sometimes red or yellow; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Specific Gravity: 2.6-2.9

Hardness: 6
Color: Brown, gray, tan, sometimes red or yellow
Luster: Vitreous to waxy

Identified June 4, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Brown, gray, tan, sometimes red or yellow; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Specific Gravity: 2.6-2.9

Formation & geological history

Formed through permineralization where organic wood materials are replaced by minerals (usually silica) in anaerobic conditions, often involving volcanic ash or sedimentary burial over millions of years.

Uses & applications

Used for ornamental carvings, jewelry (cabochons), furniture (slices for tabletops), and as decorative collectibles for enthusiasts.

Geological facts

Petrified wood is the state gem of Washington and the state rock of Mississippi. The largest concentrations are found in the Petrified Forest National Park in Arizona.

Field identification & locations

Identify by looking for preserved wood grain, bark textures, and growth rings in a stone that is heavy and cold to the touch. Found in sedimentary beds and volcanic deposits.

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