igneous, metamorphic, and sedimentary (mixed assemblage)

Mixed rounded gravel and pebbles

Polymictic clasts, likely including granite, basalt, quartzite, sandstone, and schist

AI-generated identification · may be incorrect

Mostly subrounded, weathered pebbles with varied gray, brown, red, and black colors; textures range from granular to foliated and vesicular. Individual hardness is approximately Mohs 5–7, with mostly dull to slightly vitreous luster; exact composition cannot be determined from the image alone.

Identified August 30, 2026More igneous, metamorphic, and sedimentary (mixed assemblage) →

Explore Mixed rounded gravel and pebbles in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

At a glance

Common name: Mixed rounded gravel and pebbles
Scientific name: Polymictic clasts, likely including granite, basalt, quartzite, sandstone, and schist
Category: igneous, metamorphic, and sedimentary (mixed assemblage)
Identified: August 30, 2026
Method: Standard

AI Estimated Value

Typically $0–$10 for ordinary mixed gravel; selected polished or distinctive specimens may sell for $2–$20 each.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

These are likely river, beach, or glacially transported clasts produced by erosion and abrasion of older bedrock. Their ages vary according to source rocks, commonly millions to billions of years.

Uses & applications

Used as landscaping gravel, drainage aggregate, aquarium or craft material, and educational specimens; attractive pieces may be sold for tumbling or collections.

Geological facts

The mixture is not one rock species: rounded shapes indicate transport, while contrasting colors and textures reflect multiple geological sources.

Field identification & locations

Identify individual pieces by texture: visible quartz grains suggest granite or quartzite, dark fine-grained clasts suggest basalt, layering suggests sandstone, and foliation suggests schist. Commonly found in streambeds, beaches, glacial deposits, and gravel pits.

Other igneous, metamorphic, and sedimentary (mixed assemblage) specimens

See all

Rounded quartz-rich river pebbles

Alluvial gravel; commonly quartzite, chert, and quartz-bearing sandstone fragments

sedimentary

Amethyst and mixed gemstone bracelet

Amethyst: purple quartz, silicon dioxide (SiO₂); likely accompanied by other quartz or decorative mineral beads

gemstone

Mixed Mineral Collection

Multi-mineral Assemblage (Quartz, Jasper, Obsidian, Pyrite, etc.)

mineral

Mixed rock and mineral specimen collection

Mostly undetermined from the photograph; apparent quartz-rich rocks, sandstone, granite/gneiss, and possibly iron-oxide-bearing specimens

igneous, sedimentary, metamorphic, mineral

Mixed rounded river pebbles

Polymictic alluvial gravel; likely quartz/quartzite, chert, and weathered feldspathic rocks

sedimentary

Mixed Rock and Mineral Collection

Mixed Assemblage (includes Quartz, Jasper, Feldspar, and Turquoise-colored stones)

mineral