sedimentary

Mixed Pebbles and Shell Fragments

Polylithic sedimentary aggregate and biogenic calcium carbonate

Variable hardness (3-7 on Mohs scale depending on the pebble), assorted colors including white, grey, brown, and pink, with dull to vitreous lusters.

Identified November 10, 2026More sedimentary →

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Physical properties

Variable hardness (3-7 on Mohs scale depending on the pebble), assorted colors including white, grey, brown, and pink, with dull to vitreous lusters.

Formed through mechanical weathering, water transport, and deposition in aquatic or coastal environments over recent geological epochs.

Used in landscaping, decorative ground cover, terrariums, and craft projects.

This collection represents a mixture of quartz pebbles, igneous rock fragments, and marine mollusk shell pieces smoothed by wave action.

Easily found along riverbeds, lake shores, and ocean beaches; useful for amateur lapidary work and soil drainage.

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)