sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Yellow, brown, and red tones; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Yellow, brown, and red tones
Luster: Vitreous to waxy

Identified May 3, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Yellow, brown, and red tones; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Formation & geological history

Formed from silica-rich precipitates in sedimentary environments, typically where microscopic volcanic ash or hot springs saturate sediments over millions of years, often dating from the Precambrian to present day.

Uses & applications

Used primarily in lapidary work for jewelry, cabochons, and decorative ornamental carvings. Historically used for seals and tools.

Geological facts

Jasper is an opaque variety of chalcedony. The yellow and brown hues are usually caused by the presence of iron oxides like goethite or limonite. This piece shows a beautiful 'brecciated' or fractured pattern where different mineral phases have filled cracks.

Field identification & locations

Identify in the field by its opacity (it does not transmit light even at the edges), its hardness (it will scratch glass), and its smooth, waxy feel when polished. Found in riverbeds and arid regions globally, notably in the USA, Brazil, and India.