sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Red, brown, yellow (iron inclusions), Luster: Vitreous to dull, Crystal Structure: Microcrystalline quartz/trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified April 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine-grained silica particles in volcanic ash or sedimentary deposits, often during the Cretaceous period. The color is derived from iron oxides that infiltrate the silica during formation.

Uses & applications

Used widely in lapidary arts, jewelry (cabochons), interior decoration materials, and as a collector's gemstone. Historically used for making tools due to its conchoidal fracture.

Geological facts

Jasper is an opaque variety of chalcedony. In ancient times, it was known as the 'supreme nurturer' and was worn by shamans and healers for protection.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate) and its smooth, waxy to dull fracture surface. Common in arid, desert environments or gravel beds. It cannot be scratched by a steel knife.