sedimentary
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
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 More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
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
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.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary