sedimentary

Jasper River Stone

Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)

Hardness: 6.5-7 (Mohs scale); Color: Tan/yellowish base with distinctive reddish-brown iron staining or veining; Luster: Dull to waxy; Crystal Structure: Microcrystalline quartz; Specific Gravity: 2.6-2.9.

Hardness: 6
Luster: Dull to waxy

Identified April 3, 2026More sedimentary →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through the silicification of fine-grained volcanic ash or sediment. This specimen has been significantly water-worn and weathered in a fluvial (river) or coastal environment, creating the smooth, rounded 'cobble' shape. The staining is due to iron oxidation during groundwater exposure.

Uses & applications

Used primarily for landscaping, decorative garden stones, and occasionally as lapidary material for polishing or tumbling.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning 'spotted stone.' This specific specimen shows 'differential weathering' where different minerals in the rock wear down at different rates.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife) and smooth, water-worn texture. It is commonly found in riverbeds, glacial till, and along beaches. For collectors, look for patterns that reveal interesting 'scenes' when sliced open.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Sandstone (Quartz-rich)

Arenite (SiO2)

sedimentary

Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

sedimentary