Petrified Wood

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish, and gray; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9.

Formation & Geological History

Formed through permineralization where organic wood materials are replaced by silica-rich minerals (often from volcanic ash) over millions of years. Common in Triassic to Tertiary deposits.

Uses & Applications

Used for ornamental furniture, high-end interior design slabs, lapidary art, jewelry, and as a popular collector's specimen.

Geological Facts

Famous locations include the Petrified Forest National Park in Arizona. It is a 'body fossil' where the original cellular structure is often preserved in stone.

Field Identification & Locations

Identified by its wood-like texture and growth rings preserved in a hard, stony material. Commonly found in sedimentary basins and areas with historical volcanic activity.

Identified on: 5/10/2026

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