sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Typically red due to iron inclusions; Luster: Dull to vitreous; Crystal structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.

Hardness: 6
Color: Typically red due to iron inclusions
Luster: Dull to vitreous

Identified June 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water (hydrothermal activity or silica-rich sedimentary environments). Red jasper commonly gets its color from iron oxide impurities that formed during the Proterozoic or Phanerozoic eons.

Uses & applications

Used primarily as a gemstone for jewelry, in lapidary arts for cabochons and carvings, and historically used for making scrapers and points due to its sharp conchoidal fracture.

Geological facts

Jasper is a variety of chalcedony. In ancient times, it was considered a 'rain bringer' and was used in the breastplate of the High Priest in Biblical times. It is often found as smooth river pebbles or beach stones.

Field identification & locations

Identify by its hardness (cannot be scratched with a steel knife), opaque nature, and smooth, waxy surface when wet. Commonly found in gravel pits, beach wash, and sedimentary basins worldwide.