sedimentary

Jasper River Pebble

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to ochre due to iron content. Luster: Dull to waxy. Crystal Structure: Microcrystalline quartz. Cleavage: None (conchoidal fracture hidden by weathering). Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Brownish-red to ochre due to iron content
Luster: Dull to waxy

Identified March 3, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica in sedimentary environments or volcanic ash. The rounded shape is a result of fluvial erosion (water transport) in a river or stream bed over thousands of years.

Uses & applications

Used primarily in lapidary arts, jewelry (cabochons), and as decorative landscaping stone. Historically used for making tools and seals due to its hardness.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'Jasper' is derived from the Greek 'iaspis', meaning spotted stone. It has been a popular gemstone since antiquity, mentioned in ancient Greek, Roman, and Hebrew literature.

Field identification & locations

Identify by its opacity (it does not let light through even at the edges), smooth water-worn texture, and extreme hardness (will scratch glass). Commonly found in gravel bars of rivers and on beaches.

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