sedimentary

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Hardness: 6.5-7 Mohs; Color: Brick red to brownish-red; Luster: Dull to vitreous (waxy when polished); Crystal Structure: Microcrystalline trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Brick red to brownish-red
Luster: Dull to vitreous (waxy when polished)

Identified March 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water or volcanic ash into sedimentary or metamorphic environments. Its red color comes from iron inclusions (hematite). It often forms in hydrothermal veins or as nodules in sedimentary rocks.

Uses & applications

Used primarily for jewelry (cabochons, beads), decorative carvings, lapidary art, and as an ornamental stone in landscaping. Historically used for seals and amulets.

Geological facts

Jasper has been used by humans since the Neolithic period. The name is derived from the Greek word 'iaspis', meaning 'spotted stone'. It is an opaque variety of chalcedony.

Field identification & locations

Identify in the field by its opacity (unlike translucent carnelian), smooth water-worn surface on beaches or riverbeds, and its inability to be scratched by a steel knife. Commonly found in coastal areas, river beds, and volcanic regions.