sedimentary

Red Jasper (River-worn)

Silicon Dioxide (SiO2) with Hematite inclusions

AI-generated identification · may be incorrect

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 July 4, 2026More sedimentary →

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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.