sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to ochre; Luster: Dull to waxy; Crystal structure: Microcrystalline/cryptocrystalline (trigonal); Cleavage: None; Specific gravity: 2.58-2.91

Hardness: 6
Color: Brownish-red to ochre
Luster: Dull to waxy

Identified April 8, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to ochre; Luster: Dull to waxy; Crystal structure: Microcrystalline/cryptocrystalline (trigonal); Cleavage: None; Specific gravity: 2.58-2.91

Formation & geological history

Formed through the accumulation of fine siliceous materials (silica-rich fluids or volcanic ash) that undergo diagenesis in sedimentary or volcanic environments. Often found in association with iron oxides which provide the coloring.

Uses & applications

Used primarily as decorative gemstones, for lapidary work (cabochons), historical seal stones, and in crystal healing collections.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning 'spotted stone.' It has been used for thousands of years as a gemstone and was mentioned in the Bible and ancient Greek texts.

Field identification & locations

Identify in the field by its opacity (it does not transmit light even at the edges), its conchoidal fracture (smooth, curved breaks), and its ability to scratch glass. Commonly found in riverbeds, deserts, and coastal areas.