sedimentary

Petrified Wood

Silicified Wood (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Black, brown, tan, and white; Luster: Vitreous to waxy; Structure: Pseudomorph after wood with preserved cellular structures; Cleavage: None/Conchoidal fracture.

Hardness: 6
Color: Black, brown, tan, and white
Luster: Vitreous to waxy

Identified May 1, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Black, brown, tan, and white; Luster: Vitreous to waxy; Structure: Pseudomorph after wood with preserved cellular structures; Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed via permineralization during the Cenozoic or Mesozoic eras when plant material is buried in sediment depleted of oxygen and replaced by silica-rich minerals from groundwater.

Uses & applications

Used for jewelry (cabochons), interior decor (tabletops, bookends), and as a popular lapidary material and geological collectible.

Geological facts

Petrified wood is a fossil in which the organic remains have been replaced by minerals in the slow process of being turned to stone while retaining the original structure of the wood.

Field identification & locations

Identified in the field by checking for wood-grain patterns, bark textures, and growth rings. Commonly found in areas with ancient volcanic ash or fluvial deposits like the American Southwest.