sedimentary

Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Brownish-red to earthy tones, Luster: Vitreous to greasy when wet/polished, Crystal Structure: Microcrystalline quartz, Cleavage: None (conchoidal fracture)

Hardness: 6

Identified June 19, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Brownish-red to earthy tones, Luster: Vitreous to greasy when wet/polished, Crystal Structure: Microcrystalline quartz, Cleavage: None (conchoidal fracture)

Formation & geological history

Formed from the deposition of silica-rich fluids (often from volcanic or hydrothermal activity) into sedimentary beds or cavities. These specimens appear to be river-tumbled pebbles.

Uses & applications

Commonly used in lapidary work, jewelry making (cabochons), interior ornamentation, and as a popular collection item for rockhounds.

Geological facts

Jasper is an opaque variety of chalcedony that gets its colors from mineral inclusions, typically iron oxides. Some varieties are known as 'picture jasper' because their patterns resemble landscapes.

Field identification & locations

Identify by its hardness (will scratch glass), opaque nature, and smooth, rounded appearance when found in riverbeds or beaches. Common globally in rocky coastal or fluvial environments.