sedimentary

Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Mottled reddish-brown, yellow, and grey; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Mottled reddish-brown, yellow, and grey
Luster: Vitreous to dull

Identified March 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water-rich solutions into volcanic ash or sedimentary rocks. Over geological time, the silica crystallizes into microcrystalline quartz, with mineral impurities providing the coloration.

Uses & applications

Primarily used as a gemstone for jewelry (cabochons, beads), decorative ornaments, stone carvings, and as a popular specimen for rock collectors.

Geological facts

Jasper has been used as a gemstone since antiquity; it was known in ancient Egypt, Greece, and Rome. Its name is derived from the Greek 'iaspis', meaning 'spotted stone.'

Field identification & locations

Identify in the field by its opacity (unlike translucent agate), waxy feel when polished, and characteristic multicolored mottling. Commonly found in riverbeds, volcanic regions, and sedimentary deposits worldwide.