sedimentary

Jasper (Petrified Wood variant)

Silicon Dioxide (SiO2) with iron oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Reddish-brown to tan; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Reddish-brown to tan
Luster: Vitreous to waxy

Identified March 26, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Reddish-brown to tan; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Formation & geological history

Formed through permineralization, where organic wood material is replaced by silica-rich water over millions of years. This specimen appears to be a highly jaspellized or agatized piece of fossilized wood from the Mesozoic era.

Uses & applications

Used primarily in lapidary arts for cabochons, jewelry, and decorative carvings. It is also used in landscaping and as a highly sought-after collector gemstone.

Geological facts

Jasper is an opaque variety of chalcedony. In fossilized wood, the red color is almost always due to the presence of hematite or other iron oxides during the fossilization process. Some of the most famous deposits are in the Petrified Forest National Park in Arizona.

Field identification & locations

Identify in the field by its high hardness (cannot be scratched by a steel knife), smooth waxy feel when wet, and characteristic wood-grain or bark-like patterns. Commonly found in eroded river beds or volcanic ash deposits.