sedimentary
Flint (worked into an arrowhead)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Hardness: 7 on Mohs scale. Color: Dark gray to brown-black. Luster: Waxy to dull. Fracture: Conchoidal with sharp edges. Microcrystalline/cryptocrystalline structure.
- Hardness
- 7 on Mohs scale
- Color
- Dark gray to brown-black
- Luster
- Waxy to dull
Identified More sedimentary →
Explore Flint (worked into an arrowhead) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale. Color: Dark gray to brown-black. Luster: Waxy to dull. Fracture: Conchoidal with sharp edges. Microcrystalline/cryptocrystalline structure.
Formation & geological history
Forms as nodules in sedimentary rocks, particularly chalk or limestone, from the accumulation of siliceous organism remains (like sponge spicules) in deep marine environments.
Uses & applications
Historically used for stone tools, projectile points, and fire-starting (spark generation). Modern specimens like this are often crafted for jewelry pendants, lapidary art, or replica artifacts.
Geological facts
Flint fractures with extremely sharp, predictable conchoidal edges when knapped, making it the most important material for Stone Age tools and weapons. It was heavily traded across prehistoric trade networks.
Field identification & locations
Identified by its distinctive curved, shell-like conchoidal fractures, hardness (scratches glass), and dark waxy appearance. Commonly found in chalk deposits throughout Europe, North America, and North Africa.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale
Argillaceous sedimentary rock
sedimentary
Mudstone
Argillite / Siliciclastic sedimentary rock
sedimentary