sedimentary

Jasper

Silicon dioxide (SiO2) with impurities

Hardness: 6.5-7 (Mohs), Color: Reddish-brown and mustard-green, Luster: Vitreous to dull, Crystal structure: Microcrystalline/Cryptocrystalline, Specific Gravity: 2.58-2.91

Hardness: 6

Identified May 30, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs), Color: Reddish-brown and mustard-green, Luster: Vitreous to dull, Crystal structure: Microcrystalline/Cryptocrystalline, Specific Gravity: 2.58-2.91

Formation & geological history

Formed in hydrothermal environments or as sedimentary deposits where silica-rich fluids permeate through volcanic ash or sediment, carrying iron oxides that provide color.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons), ornamental decorations, and as a popular collector's stone due to its varied patterns.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It was a favorite gemstone in the ancient world, mentioned in many historical texts.

Field identification & locations

Identify by its hardness (cannot be scratched by a steel knife), opaque nature, and smooth, waxy feel when wet. Often found in riverbeds or coastal rocky areas.