sedimentary
Red Jasper (Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick 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 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
Formation & geological history
Formed from silica-rich fluids that permeate through volcanic ash or sedimentary beds, often during the late stages of igneous activity. Its age can range from hundreds of millions to billions of years depending on the deposit.
Uses & applications
Commonly used as a gemstone for lapidary work, jewelry, ornamental items, and historically for tools like scrapers or arrowheads due to its sharp conchoidal fracture.
Geological facts
Jasper is an opaque variety of chalcedony. The red color is caused by the presence of iron (hematite) inclusions within the cryptocrystalline quartz structure. In ancient times, it was known as the 'rain bringer' by Native Americans.
Field identification & locations
Identify in the field by its opacity (even on thin edges), its characteristic 'waxy' to dull luster, and red streak. It is commonly found in gravel pits, riverbeds, and as nodules in many geological formations worldwide.
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