fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Hardness: 6.5-7 (Mohs); Color: Tan, beige, light brown; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9

Hardness: 6
Color: Tan, beige, light brown
Luster: Dull to waxy

Identified July 3, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Tan, beige, light brown; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9

Formation & geological history

Formed through permineralization where organic wood is replaced by silica (chalcedony or opal) in anaerobic conditions, often involving volcanic ash or sedimentary burial millions of years ago.

Uses & applications

Used for jewelry (cabochons), interior decoration, furniture (table tops), and as highly collectible geological specimens.

Geological facts

The fossilization process preserves the cellular structure of the original plant. The colors are often caused by trace elements like iron, manganese, or copper.

Field identification & locations

Identify by the presence of wood-like grain, bark textures, or growth rings in a stony material. Commonly found in Arizona (Petrified Forest National Park), Madagascar, and Indonesia.