sedimentary
Red Jasper (River-worn)
Silicon Dioxide (SiO2) with Hematite inclusions
Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown with dark inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Microcrystalline; Cleavage: None/Conchoidal fracture; Opaque.
- Hardness
- 6
- Color
- Reddish-brown with dark inclusions
- Luster
- Dull to sub-vitreous
Identified More sedimentary →
Explore Red Jasper (River-worn) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown with dark inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Microcrystalline; Cleavage: None/Conchoidal fracture; Opaque.
Formation & geological history
Formed when silica-rich fluids permeate through volcanic ash or sediment, often enriched with iron oxide (hematite) which provides the red color. This specific piece is a river-rounded cobble or pebble.
Uses & applications
Commonly used in lapidary work for cabochons, beads, and tumbled stones. Historically used for seals, talismans, and ornamental carvings.
Geological facts
Jasper is a dense variety of microcrystalline quartz. The name comes from the Greek word 'iaspis', meaning spotted stone. It is known for its extreme toughness due to its interlocking crystal structure.
Field identification & locations
Identify by its hardness (cannot be scratched by a steel knife) and its smooth, waxy texture when wet. Commonly found in riverbeds, gravel pits, and glacial till throughout North America, especially in the Great Lakes region and the Pacific Northwest.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Cone-in-cone structure (Limestone)
Cone-in-cone structure (Secondary Sedimentary Structure)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary