sedimentary

Jasper

Silicon dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: tan, yellow, and black patterns, Luster: Vitreous to dull, Crystal structure: Hexagonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture), Specific gravity: 2.58-2.91

Hardness: 6

Identified June 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from silica-rich fluids depositing in cracks and voids within volcanic or sedimentary rocks. The colors are derived from iron oxides or other mineral impurities during the crystallization process.

Uses & applications

Commonly used as a gemstone for jewelry, cabochons, decorative carvings, and as a popular specimen for rock tumbling and collection.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It was one of the favorite gemstones in the ancient world, often appearing in biblical and historical texts.

Field identification & locations

Identify in the field by its hardness (will scratch glass), opaque nature, and smooth conchoidal fractures. Commonly found in riverbeds, desert regions, and volcanic deposits across the Western United States and India.