sedimentary

Breccia

Sedimentary Breccia

Hardness variable (Mohs 3-7 depending on clasts and cement); rough, angular clasts embedded in a fine-grained, dull-to-earthy matrix.

Identified November 9, 2026More sedimentary →

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Physical properties

Hardness variable (Mohs 3-7 depending on clasts and cement); rough, angular clasts embedded in a fine-grained, dull-to-earthy matrix.

Forms from the accumulation and cementation of large, angular rock fragments produced by fault movement, landslides, or talus accumulation.

Used historically as an architectural stone, decorative facing, aggregate, and occasionally polished for ornamental carvings.

Unlike conglomerate, its angular clasts reveal minimal transport, meaning fragments settled very close to their parent rock source.

Identified in the field by sharp, unsorted, angular rock pieces bound together by mineral cement; found near fault zones and steep scree slopes.

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone

Arenite

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)