sedimentary
Red Jasper
Cryptocrystalline Quartz (SiO2 with Iron oxide inclusions)
Hardness: 6.5-7 on Mohs scale; Color: Red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Red to brownish-red
- Luster
- Dull to vitreous
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
Formation & geological history
Formed when silica-rich fluids permeate sedimentary rocks or volcanic ash, with the red color provided by high concentrations of iron oxide (hematite). It often forms in hydrothermal veins or as nodules in volcanic rocks.
Uses & applications
Commonly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for gemstone tumbling and crystal collecting.
Geological facts
Red Jasper has been used since antiquity in seals and ornaments, and ancient Egyptians associated it with the blood of Isis. It is a variety of chalcedony that is essentially opaque due to its high mineral inclusion content.
Field identification & locations
Identify in the field by its deep red color, extreme hardness (cannot be scratched by a steel knife), and characteristic smooth, shell-like conchoidal fracture. Found worldwide in areas like the USA (Southwest), India, and Brazil.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary