Rock Identifier
River Pebble (likely Quartzite or Chert) (Silicon Dioxide (SiO2)) — metamorphic or sedimentary
metamorphic or sedimentary

River Pebble (likely Quartzite or Chert)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: Approx. 7 (Mohs scale), Color: Tan, brown, or buff with mottling, Luster: Dull or sub-waxy (waxy when wet), Crystal structure: Microcrystalline or non-clastic, Cleavage: None/Conchoidal fracture.

Hardness
Approx
Identified More metamorphic or sedimentary →
Explore River Pebble (likely Quartzite or Chert) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App StoreGoogle Play

Physical properties

Hardness: Approx. 7 (Mohs scale), Color: Tan, brown, or buff with mottling, Luster: Dull or sub-waxy (waxy when wet), Crystal structure: Microcrystalline or non-clastic, Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed through the erosion and transport of larger rock masses (such as sandstone or metamorphic quartzite) by water. The rounded shape indicates significant travel in a river or stream bed where abrasive forces smoothed the edges.

Uses & applications

Commonly used in landscaping, decorative ground cover, aquarium gravel, and construction aggregate. If high in quartz, it can be used for tumbling by hobbyists.

Geological facts

River pebbles are smoothed by the natural process of 'attrition,' where rocks collide with one another in moving water, effectively sandblasting themselves over years or decades.

Field identification & locations

Identify by its rounded, smooth 'water-worn' texture and lack of sharp edges. These are ubiquitous in riverbeds, glacial deposits, and coastal areas.

More like this

Other metamorphic or sedimentary specimens

Small quartz-rich mineral fragment (Quartz (SiO₂), possibly milky or chalcedonic quartz) — mineral

Small quartz-rich mineral fragment

Quartz (SiO₂), possibly milky or chalcedonic quartz

mineral
Likely weathered quartz-bearing rock (uncertain identification) (Possibly quartz-rich granite or granitic aplite; exact identification requires a clearer, larger image and tests) — igneous

Likely weathered quartz-bearing rock (uncertain identification)

Possibly quartz-rich granite or granitic aplite; exact identification requires a clearer, larger image and tests

igneous
Dark gray volcanic rock, probably andesite or basalt (Fine-grained mafic–intermediate volcanic rock; likely basalt (plagioclase ± pyroxene), possibly andesite) — igneous

Dark gray volcanic rock, probably andesite or basalt

Fine-grained mafic–intermediate volcanic rock; likely basalt (plagioclase ± pyroxene), possibly andesite

igneous
Quartz (Quartz (SiO2 - Silicon Dioxide)) — Mineral

Quartz

Quartz (SiO2 - Silicon Dioxide)

Mineral
Quartz Heart or Arrowhead Shape (Silicon Dioxide (SiO2)) — mineral

Quartz Heart or Arrowhead Shape

Silicon Dioxide (SiO2)

mineral
Quartzite (Metamorphic Quartzite (primarily SiO2)) — metamorphic

Quartzite

Metamorphic Quartzite (primarily SiO2)

metamorphic