sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5 to 7 (Mohs); Color: Red, brown, and yellow due to iron inclusions; Luster: Dull to greasy; Crystal Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Red, brown, and yellow due to iron inclusions
Luster: Dull to greasy

Identified June 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water or volcanic ash, typically within sedimentary or metamorphic environments. The iron oxides (hematite and goethite) give it the red and yellow-brown colors. This specimen shows water-worn rounding, likely from a fluvial or coastal environment.

Uses & applications

Commonly used for lapidary work, jewelry making (cabochons), ornamentation, and metaphysical collecting. Historically used for tools and weapon scrapers due to its hardness.

Geological facts

Jasper has been used as a gemstone since antiquity and is mentioned in many ancient texts, including the Bible. It is a variety of chalcedony that is opaque, unlike translucent agate.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife), opacity, and smooth, waxy surface when wet. Commonly found in riverbeds, beaches, and desert pavements across the world.