sedimentary

Red Jasper (River Stone)

Jasper (Silicon Dioxide, SiO2 plus iron oxide inclusions)

Hardness: 6.5-7 on Mohs scale. Color: Deep reddish-brown to terracotta. Luster: Dull to waxy when raw, vitreous when wet. Crystal Structure: Microcrystalline/Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Deep reddish-brown to terracotta
Luster: Dull to waxy when raw, vitreous when wet

Identified April 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in fissures or between sedimentary layers, typically in volcanic or sedimentary environments. The red color comes from iron impurities. These river-worn specimens have been rounded by fluvial erosion over thousands of years.

Uses & applications

Commonly used in lapidary arts for cabochons, beads, and tumbled stones. Also used as ornamental landscaping stone and by collectors for its grounding aesthetic and smooth texture.

Geological facts

Jasper is an opaque variety of chalcedony. It has been used since antiquity for seals, talismans, and jewelry. The name comes from the Greek 'iaspis', meaning 'spotted stone'.

Field identification & locations

Identify in the field by its opacity (it will not let light through even at thin edges, unlike agate), its hardness (it should scratch glass), and its smooth, water-worn texture in riverbeds. Commonly found in gravel pits and beaches worldwide.

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