sedimentary

Polymict conglomerate

Clastic conglomerate, likely polymictic pebble conglomerate

AI-generated identification · may be incorrect

Coarse rounded to subrounded pebbles of pale quartz/quartzite and pink-gray lithic fragments cemented in a darker sandy matrix; grains are mainly hard, translucent to opaque, with dull to slightly granular luster. Typical quartz hardness is Mohs 7; bulk-rock hardness and specific gravity vary with cement and clasts.

Identified September 10, 2026More sedimentary →

Explore Polymict conglomerate in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Forms when gravel is transported and rounded by rivers, beaches, or alluvial fans, then buried, compacted, and cemented by silica, carbonate, or iron oxides. Its exact geological age cannot be determined from the image; conglomerates occur from Precambrian to modern deposits.

Uses & applications

Used locally as decorative stone, landscaping aggregate, and occasionally building stone; attractive polished pieces may be sold as curios or lapidary material.

Geological facts

The rounded clasts indicate substantial transport before lithification, while the mixed clast types make it polymictic. Pink coloration may reflect feldspar or iron-oxide staining.

Field identification & locations

Identify it by abundant pebble-sized rounded clasts visibly embedded in a finer matrix; a hand lens, dilute acid test for carbonate cement, and hardness testing can refine identification. Common in ancient river-channel and shoreline deposits worldwide.