Rock Identifier
River Pebbles (Stream-rounded rocks) (Fluvial Detritus (varied mineralogy)) — Mixed (predominantly sedimentary and igneous)
Mixed (predominantly sedimentary and igneous)

River Pebbles (Stream-rounded rocks)

Fluvial Detritus (varied mineralogy)

Hardness: 5-7 (Mohs scale), Color: shades of grey, tan, and muted pink, Luster: dull to earthy (waxy if wet), Structure: clastic or crystalline depending on specific pebble, Shapes: sub-rounded to rounded with smooth surfaces.

Identified More mixed (predominantly sedimentary and igneous) →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Hardness: 5-7 (Mohs scale), Color: shades of grey, tan, and muted pink, Luster: dull to earthy (waxy if wet), Structure: clastic or crystalline depending on specific pebble, Shapes: sub-rounded to rounded with smooth surfaces.

Formation & geological history

Formed through mechanical weathering and fluvial erosion. These are small fragments of larger rock formations (like granite, sandstone, or limestone) that have been transported by moving water, smoothing the edges over thousands of years.

Uses & applications

Commonly used in landscaping, decorative stone, construction aggregate, and gravel paths. High-quality smooth stones are also used in spa therapy (hot stones).

Geological facts

The roundness of these stones is a direct indicator of the energy of the water that transported them and the distance they traveled; the smoother the stone, the longer the journey.

Field identification & locations

Identify in the field by their smooth, rounded edges and lack of sharp fractures, usually found in riverbeds, glacial deposits, or beaches. Collectors value them for rock tumbling or decorative garden fillers.

More like this

Other mixed (predominantly sedimentary and igneous) specimens

River Rock (Glacial Cobbles) (Fluvial Alluvium (Mixed lithology including Quartzite, Basalt, and Granite)) — Mixed (predominantly sedimentary and igneous)

River Rock (Glacial Cobbles)

Fluvial Alluvium (Mixed lithology including Quartzite, Basalt, and Granite)

Mixed (predominantly sedimentary and igneous)
Engineered Quartz Stone (Agglomerated Quartz (SiO2 + Polymer Resin)) — mineral-based composite

Engineered Quartz Stone

Agglomerated Quartz (SiO2 + Polymer Resin)

mineral-based composite
Amethyst (Chevron or Banded Amethyst) (Silicon Dioxide (SiO2) with Fe3+ impurities) — mineral

Amethyst (Chevron or Banded Amethyst)

Silicon Dioxide (SiO2) with Fe3+ impurities

mineral
Mixed Tumbled Gemstones and River Rocks (Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)) — Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)

Mixed Tumbled Gemstones and River Rocks

Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)

Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)
Amethyst (Raw Quartz) (Silicon Dioxide (SiO2)) — mineral

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2)

mineral
Fluorite (Calcium Fluoride (CaF2)) — mineral

Fluorite

Calcium Fluoride (CaF2)

mineral