sedimentary
Petrified Wood / Red Jasper
Silicified wood (primarily Silicon Dioxide, SiO2)
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 More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
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.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary