Rock Identifier
Petrified Wood (Petrified Wood (Silicified Wood)) — fossil
fossil

Petrified Wood

Petrified Wood (Silicified Wood)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs), Color: Brown, red, yellow, orange (due to iron oxides), Luster: Waxy to dull, Crystal structure: Microcrystalline (chalcedony/quartz replacing wood structure)

Hardness
6
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Physical properties

Hardness: 6.5-7 (Mohs), Color: Brown, red, yellow, orange (due to iron oxides), Luster: Waxy to dull, Crystal structure: Microcrystalline (chalcedony/quartz replacing wood structure)

Formation & geological history

Forms when plant material is buried by sediment and protected from decay by oxygen and organisms. Groundwater rich in dissolved solids flows through the sediment, replacing the original plant material with silica, calcite, pyrite, or another inorganic material.

Uses & applications

Used primarily in lapidary arts for cabochons, carvings, bookends, and decorative items. Also collected as specimens.

Geological facts

The varied colors in petrified wood come from trace elements. Iron produces reds, browns, and yellows; copper and cobalt create greens and blues; manganese creates blacks.

Field identification & locations

Identified by the preservation of wood grain, rings, and bark structures. Common in areas with past volcanic activity and ancient forests. Look for heavy, dense stones with wood-like patterns.

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