sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, yellow (iron inclusions), Luster: Vitreous to dull, Crystal Structure: Microcrystalline quartz/trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, yellow (iron inclusions), Luster: Vitreous to dull, Crystal Structure: Microcrystalline quartz/trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the accumulation of fine-grained silica particles in volcanic ash or sedimentary deposits, often during the Cretaceous period. The color is derived from iron oxides that infiltrate the silica during formation.
Uses & applications
Used widely in lapidary arts, jewelry (cabochons), interior decoration materials, and as a collector's gemstone. Historically used for making tools due to its conchoidal fracture.
Geological facts
Jasper is an opaque variety of chalcedony. In ancient times, it was known as the 'supreme nurturer' and was worn by shamans and healers for protection.
Field identification & locations
Identify in the field by its opacity (unlike translucent agate) and its smooth, waxy to dull fracture surface. Common in arid, desert environments or gravel beds. It cannot be scratched by a steel knife.
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