sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Variegated grays, browns, and tans (as shown); Luster: Vitreous to greasy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58–2.91.

Hardness: 6
Color: Variegated grays, browns, and tans (as shown)
Luster: Vitreous to greasy

Identified April 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine silica and other minerals in hydrothermal veins or sedimentary environments. It is often created during the silicification of volcanic ash or sediments over millions of years.

Uses & applications

Used primarily for ornamental purposes, tumbled stones for collection, lapidary work, jewelry (cabochons), and as decorative architectural accents.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek word 'iaspis', meaning 'spotted stone'. In ancient history, it was believed to ward off evil spirits and protect against drought.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate), conchoidal fracture, and extreme hardness. It won't be scratched by a steel knife. Common locations include Brazil, India, and the Western United States.