fossil

Petrified Wood

Silicified Wood (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Tans, browns, and grays; Luster: Dull to waxy; Structure: Cryptocrystalline with visible woody grain and growth rings; Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Tans, browns, and grays
Luster: Dull to waxy

Identified July 3, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Tans, browns, and grays; Luster: Dull to waxy; Structure: Cryptocrystalline with visible woody grain and growth rings; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed through permineralization, a process where organic material is replaced by minerals (usually silica) over millions of years. This specimen likely dates from the Mesozoic or Cenozoic eras.

Uses & applications

Commonly used for lapidary work, jewelry making, decorative bookends, and as a popular educational geological specimen for collectors.

Geological facts

Petrified wood is the state fossil of Arizona. The process happens underground when wood is buried under sediment and anaerobic conditions prevent decay while mineral-rich water flows through.

Field identification & locations

Identify by looking for distinct grain patterns, knobby bark-like textures, or tree rings that remain even though the material is now stone. Found worldwide in ancient sedimentary basins.