sedimentary (microcrystalline quartz)

Jasper River Pebble

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Muted earthy tones, primarily deep red, brown, and olive green with a matte finish. Luster: Dull to waxy. Crystal structure: Cryptocrystalline (hexagonal/trigonal). Cleavage: None, exhibits conchoidal fracture. Specific Gravity: 2.58-2.91.

Hardness: 6
Luster: Dull to waxy

Identified March 24, 2026More sedimentary (microcrystalline quartz) →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich fluids in volcanic ash or sedimentary beds, often during the Proterozoic or Paleozoic eras. This specific specimen has been further shaped by fluvial erosion (river weathering), which accounts for its smooth, rounded, pebble-like appearance.

Uses & applications

Commonly used for lapidary work, cabochons for jewelry, decorative stones for landscaping, and as a durable material for stone tools in prehistoric times. It is also a popular specimen for rock tumbling and amateur collecting.

Geological facts

Jasper has been a prized gemstone for millennia; it was used in ancient Mesopotamia to make cylinder seals and is mentioned in various historical biblical texts. Its diverse colors are usually caused by impurities of iron oxides (red/brown) or chlorites (green).

Field identification & locations

Identify in the field by its extreme hardness (cannot be scratched by a steel knife), smooth water-worn surface, and lack of visible grains. It is very commonly found in gravel pits, riverbeds, and beach deposits globally, particularly in areas with volcanic history.