sedimentary

Jasper

Silicon dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Mottled green, brown, and red; Luster: Vitreous to waxy (when wet/polished); Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Opaque.

Hardness: 6
Color: Mottled green, brown, and red
Luster: Vitreous to waxy (when wet/polished)

Identified July 12, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Mottled green, brown, and red; Luster: Vitreous to waxy (when wet/polished); Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Opaque.

Formation & geological history

Formed through the deposition of silica from water or volcanic ash, often in hydrothermal environments or as sedimentary deposits. The colors are derived from mineral impurities like iron (hematite) and chlorite.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons), ornamentation, and as a collector's specimen. Historically used for making seal stones and tools.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' is derived from the Greek word 'iaspis', meaning 'spotted stone'. It is known for its wide variety of patterns and colors.

Field identification & locations

Identify in the field by its opacity, smoothness, and hardness (it will scratch glass). Often found in riverbeds or coastal areas as rounded cobbles. Look for colorful, waxy textures on broken surfaces.