sedimentary
Chert (Likely Jasper)
Microcrystalline Quartz (SiO2)
Hardness: 7 Mohs scale; Color: Honey-yellow, orange-brown, and white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 Mohs scale
- Color
- Honey-yellow, orange-brown, and white
- Luster
- Waxy to vitreous
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 Mohs scale; Color: Honey-yellow, orange-brown, and white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed via the accumulation of silica-rich microfossils on the seafloor or through the replacement of limestone by silica-saturated groundwater. This specimen displays the typical conchoidal fractures of cryptocrystalline silica.
Uses & applications
Historically used for making stone tools (arrowheads). Modern uses include lapidary work, jewelry (tumbled stones), and as a decorative landscaping rock.
Geological facts
Chert and its varieties like Jasper and Flint were among the first resources used by early humans for tools because of how they shatter into extremely sharp edges.
Field identification & locations
Identified in the field by its waxy luster, hardness (it will scratch glass), and smooth, shell-like (conchoidal) fracture surfaces. Commonly found in sedimentary rock layers or as nodules in limestone.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary