sedimentary

Petrified Wood / Red Jasper

Silicified wood (primarily Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Red, brown, tan; Luster: Waxy to vitreous; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9

Hardness: 6
Color: Red, brown, tan
Luster: Waxy to vitreous

Identified June 21, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Red, brown, tan; Luster: Waxy to vitreous; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9

Formation & geological history

Formed through permineralization where organic wood materials are replaced by silica (chalcedony or quartz) over millions of years, often in volcanic ash or sedimentary fluvial environments.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons), interior decor, and as educational geological specimens.

Geological facts

The red coloring is typically due to iron oxide (hematite) impurities during the fossilization process. Petrified wood is the state gem of Washington and the state fossil of Arizona.

Field identification & locations

Identify by looking for preserved wood grain, bark textures, or ring patterns. Field identification is aided by its high hardness (it will scratch glass) and waxy luster when broken.