fossil

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of cellulose)

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, tan, and cream; Luster: Dull to waxy; Structure: Preservation of original wood grain and cellular structure; Specific Gravity: 2.6-2.9

Hardness: 6
Color: Reddish-brown, tan, and cream
Luster: Dull to waxy

Identified July 8, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, tan, and cream; Luster: Dull to waxy; Structure: Preservation of original wood grain and cellular structure; Specific Gravity: 2.6-2.9

Formation & geological history

Formed when plant material is buried by sediment and protected from decay by oxygen and organisms. Gradiuelly, groundwater rich in dissolved solids (silica) flows through the sediment, replacing the original plant material with mineral matter over millions of years.

Uses & applications

Used for ornamental carvings, jewelry (cabochons), furniture (slices for tables), and as educational or collector museum specimens.

Geological facts

Petrified wood is the state gemstone of Washington and the state rock of Mississippi. The famous Petrified Forest National Park in Arizona contains wood that is approximately 225 million years old.

Field identification & locations

Look for distinctive rings, bark textures, or knots similar to living wood, but with the weight and hardness of stone. It is commonly found in sedimentary beds near volcanic ash deposits.

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