sedimentary
Beach Pebble / Agate-bearing Chert Pebble
Microcrystalline Quartz (SiO2) with Inclusion Minerals
AI-generated identification · may be incorrectHardness: 6.5-7 on Mohs scale; Color: Mottled brown, tan, translucent white, and dark grey/black patches; Luster: Vitreous to waxy when wet/smooth; Cleavage: None (conchoidal fracture); Specific Gravity: ~2.6-2.75.
- Hardness
- 6
- Luster
- Vitreous to waxy when wet/smooth
Identified More sedimentary →
Explore Beach Pebble / Agate-bearing Chert Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Mottled brown, tan, translucent white, and dark grey/black patches; Luster: Vitreous to waxy when wet/smooth; Cleavage: None (conchoidal fracture); Specific Gravity: ~2.6-2.75.
Formation & geological history
Formed through the precipitation of silica in sedimentary environments or basaltic cavities, followed by erosion, transport, and natural water-smoothing in rivers or ocean shorelines.
Uses & applications
Primarily collected as a beachcombing keepsake, used in lapidary work for rock tumbling, decorative gravel, and landscape design.
Geological facts
Water-rounded pebbles often travel tens or hundreds of miles down rivers to beaches, undergoing continuous natural polishing along the way.
Field identification & locations
Look for rounded, smooth shapes with translucent patches of chalcedony/quartz and dark inclusions. Commonly found on ocean beaches, lake shores, and river beds worldwide. Tumbles well in a rock tumbler.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary