sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5–7 on Mohs scale. Color: Opaque red with brown or yellow swirls. Luster: Dull to vitreous (waxy when polished). Crystal structure: Microcrystalline/Cryptocrystalline trigonal. Cleavage: None (conchoidal fracture). Specific gravity: 2.58–2.91.

Hardness: 6
Color: Opaque red with brown or yellow swirls
Luster: Dull to vitreous (waxy when polished)

Identified April 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water-rich environments or during the alteration of volcanic ash. It often contains iron oxide impurities which give it the red color. These can range in age across almost all geological eras.

Uses & applications

Commonly used for lapidary work, jewelry (cabs, beads), carved ornaments, and as a decorative stone in landscaping. Historically used for making tools and seals.

Geological facts

Ancient Egyptians often wore red jasper as amulets to boost strength. It is an opaque variety of chalcedony and is commonly known as the 'supreme nurturer' in gemstone folklore.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife) and its smooth, shell-like fracture pattern. Commonly found in riverbeds, desert locations, or near volcanic regions where silica-rich fluids were present.