sedimentary

Red Jasper (Quartz)

Silicon Dioxide (SiO2) with Iron impurities

Hardness: 6.5-7 (Mohs); Color: Brick red to brownish-red due to iron inclusions; Luster: Dull to vitreous when polished; Crystal structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific gravity: 2.6-2.9

Hardness: 6
Color: Brick red to brownish-red due to iron inclusions
Luster: Dull to vitreous when polished

Identified May 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic or sedimentary rocks, or as nodules in chemical sedimentary deposits. Often found in proximity to ancient hydrothermal activity or volcanic ash beds.

Uses & applications

Used primarily as a decorative gemstone for jewelry (cabochons), lapidary art, and rock collections. Industrially, jasper varieties are occasionally used for abrasives or as building facing material.

Geological facts

Red jasper has been used since antiquity in seals and amulets; it was known in ancient Egypt as the 'blood of Isis'. It is an opaque variety of chalcedony.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and its characteristic opaque, waxy appearance. Commonly found in river beds or desert pavement in regions with volcanic history like Oregon, Idaho, or coastal California.

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