sedimentary
Jasper with Agate Inclusions
Silicon Dioxide (SiO2) - variety of Quartz/Chert
Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, and reddish matrix with translucent grey/blue agate pockets; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 6
- Luster
- Waxy 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 scale); Color: Brown, tan, and reddish matrix with translucent grey/blue agate pockets; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the process of silicification, where silica-rich fluids permeate porous volcanic ash or sedimentary rock, precipitating microcrystalline quartz. Often found in areas of ancient volcanic activity or lake beds dating from the Cretaceous to Neogene periods.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons), interior decoration items like bookends, and as a popular specimen for mineral collectors due to its unique patterns.
Geological facts
Jasper is typically opaque because of its high mineral impurities (often iron), while the clear patches in this specimen represent 'agate,' which is the translucent variety of chalcedony. This specific combination is often found in 'Brecciated Jasper' or 'Orbicular Jasper' formations.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by a steel knife), conchoidal (shell-like) fracture, and the smooth, waxy texture of the broken surfaces. Commonly found in river beds or desert regions in the Western United States (Oregon, Idaho, California) and Brazil.
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