sedimentary
Chert with Quartz Vein
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale); Color: Dark brown/black with a cream/tan vein; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture)
- Hardness
- 7 (Mohs scale)
- Color
- Dark brown/black with a cream/tan vein
- Luster
- Waxy to dull
Identified More sedimentary →
Explore Chert with Quartz Vein in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale); Color: Dark brown/black with a cream/tan vein; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture)
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine environments; the vein formed later by hydrothermal fluids filling a fracture.
Uses & applications
Historically used for stone tools due to sharp edges; currently used for decorative pebbles and lapidary practice.
Geological facts
Dark varieties of chert are often called flint. The light-colored line is a 'wishing stone' feature, formed when a different mineral fills a crack in the host rock.
Field identification & locations
Identify by its extreme hardness (scratches glass) and smooth, water-worn texture. Common on beaches and in riverbeds globally.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary