sedimentary

Jasper

Silicon Dioxide (SiO2) with impurities

Hardness: 6.5-7 (Mohs scale), Color: Red, brown, yellow, and green (opaque), Luster: Dull to Vitreous (greasy when polished), Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified March 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich fluids in volcanic ash or sedimentary environments. The opaque color is caused by the inclusion of iron oxides or other mineral impurities during the silicification process. Age varies widely from Precambrian to recently formed.

Uses & applications

Commonly used in jewelry (cabochons), lapidary art, ornaments, and historical tools like scrapper/arrowheads. It is also a popular collector's stone for its unique patterns and color banding.

Geological facts

Jasper has been used as a gemstone since antiquity and is mentioned in various historical texts including the Bible and Greek mythology. Known as the 'supreme nurturer,' it was historically believed to provide protection and support during times of stress.

Field identification & locations

Identify in the field by its opacity (it will not let light through even at thin edges, unlike agate), smooth waxy feel, and conchoidal fracture (curved, glass-like breaks). Found globally, notably in the United States (Oregon, Idaho), India, Brazil, and Madagascar.