sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5–7 (Mohs); Color: Deep brownish-red with dark iron-rich layers; Luster: Dull to waxy; Crystal Structure: Microcrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Deep brownish-red with dark iron-rich layers
Luster: Dull to waxy

Identified April 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments during diagenesis. The dark coloration is due to high iron oxide content incorporated during its formation in varied geological ages ranging from Precambrian to Cenozoic.

Uses & applications

Commonly used as a decorative gemstone for jewelry (cabochons), ornamentation, and in industrial applications for precision burnishing or as a sturdy aggregate.

Geological facts

Jasper is an opaque variety of chalcedony. Brown jasper specifically is often associated with the 'grounding' properties in metaphysical folklore. Many specimens contain preserved fossilized structures from prehistoric seabeds.

Field identification & locations

Identify in the field by its high hardness (will scratch glass and steel), opaque appearance (it does not let light through even at thin edges), and smooth, waxy feel when water-worn. Common in riverbeds and mountainous terrain worldwide.