mineral

Red Jasper (Opaque Chalcedony)

Silicon Dioxide (SiO2) with Hematite impurities

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish red, Luster: Vitreous to dull, Crystal Structure: Trigonal (Microcrystalline), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified May 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich fluids filling cavities in volcanic or sedimentary rocks, often associated with hydrothermal activity. Its red color is derived from iron (hematite) inclusions incorporated during formation.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons, beads), decorative ornaments, and as a collector's stone. Historically used for making tools due to its conchoidal fracture.

Geological facts

The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used in jewelry for thousands of years, appearing in the artifacts of ancient Egypt and Mesopotamia.

Field identification & locations

Identify in the field by its opacity (unlike translucent carnelian), hardness (it will scratch glass), and its distinct red color. Commonly found in river beds, beaches, and areas with volcanic history like the Western US, Brazil, and India.