sedimentary
Chert (specifically Flint or Nodular Chert)
Silicon dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Tan, beige, or cream; Luster: Dull to waxy; Structure: Microcrystalline; Fracture: Conchoidal (shell-like curves)
- Hardness
- 7 on Mohs scale
- Color
- Tan, beige, or cream
- Luster
- Dull to waxy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Tan, beige, or cream; Luster: Dull to waxy; Structure: Microcrystalline; Fracture: Conchoidal (shell-like curves)
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine environments, often as nodules within limestone or chalk beds.
Uses & applications
Historically used for stone tools (knapping) and fire-starting; currently used for decorative stone, landscaping, and as a raw material for ceramics and glass.
Geological facts
Chert breaks with a very sharp edge, which made it the primary material for arrowheads and spears for thousands of years. It is essentially a non-crystalline form of quartz.
Field identification & locations
Identify by its 'flinty' waxy surface and conchoidal fracture patterns. These specimens appear to be weathered nodules collected from a gravel pit or limestone deposit.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary