sedimentary

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on Mohs scale; Color: Opaque brick red to brownish-red; Luster: Dull or vitreous (glassy); Crystal Structure: Prismatic/Cryptocrystalline quartz; Cleavage: None; Specific Gravity: 2.58 - 2.91.

Hardness: 6
Color: Opaque brick red to brownish-red
Luster: Dull or vitreous (glassy)

Identified March 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the precipitation of silica from volcanic fluids or in hydrothermal veins. Some varieties originate from consolidated silica mud or ash. In a sedimentary context, it often forms as nodules or large masses within iron-bearing sandstone or limestone formations.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and carvings. Historically used for architectural trim, vases, and seal stones. In the industrial sector, it can be used as fill material or for abrasive purposes.

Geological facts

Red jasper's color is primarily due to inclusions of iron oxide (hematite). In ancient cultures, it was known as the 'rain bringer' and was used as an amulet against bad luck and for protection. Its name is derived from the Greek word 'iaspis', meaning spotted stone.

Field identification & locations

Identify in the field by its high hardness (it cannot be scratched by a steel knife), smooth conchoidal (shell-like) fracture, and complete opacity. Found worldwide, frequently in riverbeds, beaches, and desert environments like Arizona, South Africa, and India. It is a favorite for rock tumblers.