sedimentary

Riverstone Jasper (Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Muted greens, yellows, and browns with a mottled pattern; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (Conchoidal fracture); Specific gravity: 2.6–2.7.

Hardness: 6
Color: Muted greens, yellows, and browns with a mottled pattern
Luster: Waxy to vitreous

Identified April 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water solutions into voids or cracks in other rock types. Over geological time, these nodules are weathered out and smoothed by water action in riverbeds.

Uses & applications

Used primarily for river rock landscaping, decorative gravel, jewelry (as tumbled stones or cabochons), and as a tool for lithotherapy or lapidary practice.

Geological facts

Jasper is an opaque variety of chalcedony. The variety of colors is usually due to the inclusion of iron oxides. This specific specimen shows signs of natural water-smoothing, typical of stones found in active or ancient riverbeds.

Field identification & locations

Identify in the field by its smoothness, lack of visible grain (unlike sandstone), and its inability to be scratched by a steel knife. It is often found in riverbanks and gravel pits.

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

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Sandstone

Arenite (primarily SiO2)

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Shale or Slaty Mudstone

Argillaceous sedimentary rock

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Chert Breccia

Brecciated Chert (Microcrystalline Silica)

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Sandstone (Quartz-rich)

Arenite (SiO2)

sedimentary

Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

sedimentary