fossil

Petrified Wood

Silicified wood (primarily SiO2)

Hardness: 6.5-7 (Mohs scale); Color: green, tan, reddish-brown, and gray; Luster: waxy to vitreous; Structure: cryptocrystalline silica preserving organic textures; Cleavage: none (conchoidal fracture).

Hardness: 6
Color: green, tan, reddish-brown, and gray
Luster: waxy to vitreous

Identified July 12, 2026More fossil →

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Physical properties

Formation & geological history

Formed through permineralization, where organic wood material is replaced by minerals (usually silica) from volcanic ash or groundwater over millions of years, often dating to the Triassic or Jurasic periods.

Uses & applications

Used for decorative ornaments, lapidary art, jewelry, furniture (such as tabletops), and as prized museum or private collector specimens.

Geological facts

The green coloration in this specimen is often caused by the presence of iron, chromium, or copper during the mineralization process. Entire petrified forests exist, such as the one in Arizona.

Field identification & locations

Identify by looking for preserved wood grain, bark textures, or growth rings in a heavy, stony material. Found in sedimentary layers worldwide, notably in the Western USA, Madagascar, and Indonesia.